Alicorn Milk

by Moon Dreams

First published

For months, a young Twilight Sparkle's mind has burned with the question, "What do baby dragons eat?" Tonight, a visit with her beloved mentor will reveal the answer to be more mysterious and wondrous than she could have ever imagined.

After months of research and experimentation, filly Twilight Sparkle is at her wit's end in her search for something nourishing to feed her newly-hatched baby brother Spike. Desperate for a solution, she pays a surprise visit to her beloved mentor Princess Celestia long after bedtime has come and gone.

The Princess will provide an answer, though not in a way that either of them expects, as Twilight works feverishly to unlock the long-hidden mysteries of alicorn biology and deviant sexuality.

Tonight, it's Celestia's turn to learn a lesson: even a princess has no secrets in the sacred light of Science.


Contains: Herm/Futalestia, semen worship, genital worship, anal worship, beloved mentor worship, science worship, fantasy fetish gear, regular fetish gear, bondage, softcore foalcon, softcore adultcon, masturbation, edging, prodigious screaming orgasms, avian metaphors, dairy metaphors, Princess abuse by a minor.

What does the Princess say? (A: Moo)

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Twilight Sparkle turned over in her giant new ultra-soft bed and buried her head in her giant new ultra-soft pillows, clutching Smarty Pants tightly to her chest.

The Princess had given these to her, she reminded herself. These were the Princess’s own personal pillows, and she loved them, and there was absolutely no logical reason why a big filly like her should take longer than the equine average of fifteen minutes to fall asleep in a perfect, regal bed, with perfect, regal pillows.

She stared into the shadows on the far side of the room, listening to the metronomic ticking of the clock on her wall. She felt a tight knot of tension as she waited.

After just a few minutes, a muffled mewling cut across the room, and then went silent.

Twilight sighed. There was no reason a pony should take hours and hours to fall asleep… except for that.

Carefully setting Smarty Pants on the far side of the bed before shoving aside the layered blankets, Twilight dropped to the floor and crossed the room to Spike’s little bassinet.

The newly hatched dragon was on his side in a little nest of blankets of his own, curled up almost into a ball, his tail stretched up between his legs and into his mouth where he suckled on the tip. His eyes were closed and he appeared to be asleep, but his face was contorted in a little grimace of discomfort and after a few moments he made another small cry, before sucking harder.

Twilight felt more than a little like crying herself. Levitating over her trusty notebook of checklists, she looked down the array of crossed-off items.

Amethyst and aquamarine… limestone and lodestones… marble and mica… all the way through to zebra jasper and zinc blende. Every stone and mineral that she could get her hooves on, and a few that she had to ask the Princess to find for her, and not one would the infant dragon find suitable for more than a nibble.

It was the same with the milk. Looking around her room, Twilight saw empty bottles for every kind of milk that you could buy in Canterlot stacked on the desks and drawers, everything from cow to soy.

The problem was, nopony actually knew what it was that baby dragons were supposed to eat. Apparently she was never really supposed to hatch Spike’s egg in the first place, and now that she had, nopony really knew what to do with him. Even the Princess didn’t know, though she had assured Twilight that dragons could go for long periods without nourishment and never starved. Still, dragons were known to enter a sort of hibernation if food sources grew too scarce, and the last thing Twilight wanted to do so soon after gaining a new baby brother was to lose him again.

Leaning down into the bassinet, Twilight gave the little green lizard a peck on the cheek. Although he wasn’t in immediate danger, the whole situation made Twilight feel so helpless. Even the powers of science and deduction seemed unable to help her this time; she couldn’t think of any more experiments to perform.

Feeling that tightness in her chest return, Twilight gazed despondently back at her bed.

She needed to face facts: she wasn’t getting any sleep tonight. Not with an unsolved problem practically staring her right in the face.

Wiping her nose, Twilight made a decision.

Gathering her pencil and notebook, Twilight took a moment to tuck Spike into his bed, and then Smarty Pants into hers, before opening the bedroom door and slipping out into the corridor beyond.

As warm and as bustling as Canterlot Castle was during the day, with sunlight pouring in through the wide open windows and servants giving her nods and smiles as they passed, at night Canterlot Castle was like a different place altogether. The corridors seemed wide and empty; heavy curtains were draped across every window; the few magical torches mounted on the walls provided flickering light and deep shadows. No servants were permitted near the royal suite at night; only the occasional guard patrolled the halls.

Twilight didn’t waste any time in the wide open gloom; she immediately turned and made for the other end of the long hallway, her tiny hooves clacking against the polished marble floor. Soon she came upon the two guards stationed on either side of the aureate royal doorway.

While the guards didn’t scare her nearly as much as they did when she first moved to the castle, they could still be intimidating at times, with their heavy golden armor and their cold hard faces nothing like the kind sweet Princess they were supposed to protect. She began to regret leaving Smarty Pants behind.

Once it became clear that the guards weren’t going to acknowledge her on their own, she scuffed her hoof on the floor and cleared her throat before saying, “Um… excuse me.”

The eyes of the closest guard flicked towards her.

She fidgeted. “Um… may I see the Princess, please? I know it’s late….”

“Nopony is allowed to see the Princess after hours without prior authorization from the commander of the night’s watch,” the guard rattled off in monotone.

Twilight paused her fidgeting as she looked up at the guard. It felt like all the frustration of the past few hours were bubbling to the surface, and she felt her eyes moisten as her lip trembled.

“But… but she said that I could see her anytime I wanted if it was important! And it’s important!”

The guards looked at each other silently for a few moments before the closest one cleared his throat.

“I… suppose Her Royal Highness did mention something about an exception for a certain Miss Twilight Sparkle. If it’s an emergency.”

Twilight Sparkle nodded eagerly, her tears already beginning to fade away. Perhaps Spike’s hunger wasn’t an “emergency” per se, but surely extreme sleep deprivation would count. Or… perhaps it was only regular sleep deprivation.

Opening her notepad, Twilight made a quick note to look up the exact physical limits of the equine form when next she visited the library.

“…Very well, then,” continued the guard after a few moments, for once looking a bit unsure of himself. “I suppose I’ll just knock –“

Twilight, who had spent more time inside the royal quarters since moving to the castle than in her own, quickly pulled open the golden door with her magic and stepped inside, eager to get to the Princess and away from that dark hallway as swiftly as she could.

As the enchanted door closed silently and automatously behind her, Twilight took a moment to look around the room.

The entrance to the royal suite, which the Princess referred to as her “parlor,” was large, with many bookshelves and display cases lining the walls, featuring titles and knick-knacks from periods stretching back thousands of years. An alicorn-sized desk dominated the area near the door, simple, sturdy, elegantly carved from some imported wood, with neat stacks of paperwork separated into different bins and various quills and inkwells and the like arranged across the top of it.

The air was clean and fresh, the colors were muted, the carpet under Twilight’s hooves was thick and soft, putting a pleasant pressure on her soles, and – best of all – everything in the room was clean, orderly, and wherever practical, arranged in alphabetical order.

Twilight was still trying to convince the Princess to let her and Spike live here in Celestia’s own quarters. The Princess had said no, but promised frequent sleepovers.

The side of the room opposite the parlor was what Celestia referred to as her “den,” and featured several floor-to-ceiling draped windows that would, during the day, provide a view of much of Equestria backed by the rising sun. Off to the side was the door to the bedroom proper where the Princess kept her more private belongings, exquisitely-crafted and rarely-used formal wear, and an ornate alicorn-sized bed that was so soft a filly could almost get swallowed by it if she wasn’t careful. And in the rear, right-corner of the den was the large, roaring fireplace that provided most of the soft, warm light that the Princess so enjoyed. In front of it was a sprawling purple pillow, not too thick, and with a sizable golden cylindrical edge on the side farthest from the fireplace, in case a pony wanted to sit back against it instead of lying down while she read a book or simply taking a nap by the fire.

From that far corner of the room Twilight heard a strange, slick, fleshy sound, and what sounded like the Princess’s labored breathing.

Peeking around the side of the desk, Twilight saw the Princess in profile, sitting on her generous rump and leaning back against the edge of the floor pillow, her long hinds spread and pointed towards the fireplace. Though her ethereal mane and tail blocked the view of most of her body, Twilight could see that she was wearing some kind of strange black-and-silver outfit including thick stockings, a saddle, and an elaborate head-mask that seemed to cover her entire face.

Visible underneath a network of sable faux-leather straps, the Princess’s sides sheened like pearl as they heaved, the graceful arch of her neck thrown back and her normally-angelic voice seeming almost crude as she grunted like a farm girl pulling a plow. The same hooves that signed treaties and graced the lands of a hundred nations were wrapped around some thick rod that speared out from between her hind legs, jerking up and down like she was trying to… like she was trying to….

…Come to think of it, Twilight had no idea what she was trying to do. Her nose wrinkling in bafflement, Twilight called out to her.

“Princess?”

Princess Celestia froze, only her deep breathing giving any sign that she was alive. The head-mask covered everything except for her nostrils and her ears, one of which perked almost painfully erect and pointed towards Twilight. For a few moments, the only sound was the dull crackle of the fireplace.

“Princess Celestia?” Twilight repeated, more hesitantly this time.

The Princess’s horn glowed as she undid the leather bindings covering her eyes and mouth. A moment later her hooves jerked back and the snake-like thing between her legs disappeared.

“Twiwight Shparkle, I –“ the Princess began, before blinking her deep lavender eyes and using magic to tear a thick metal bit out of her mouth, letting it dangle from a strap attached to her head-mask.

“Twilight Sparkle,” she began again, sounding almost afraid. “What… how…?”

The Princess turned and stared at the grand golden doors, her mouth opening and closing. Twilight Sparkle had never seen the Princess so mortified, and it was a bit disconcerting.

The filly stared down at a hoof as she scuffed it against the carpet. “Are you okay, Princess? Did I do something wrong?”

The Princess finally glanced down at Twilight, her breathing finally starting to come under control even as sweat dripped from the tip of her chin.

“…Twilight Sparkle, what are you doing here?” The Princess began, her voice fast and sharp. “More to the point: how are you here? I put you to bed hours ago!”

Twilight stared right back into the Princess’s wide eyes. After a few moments she felt her own eyes begin to water as her lip trembled.

The Princess blinked again before angling her body slightly more towards Twilight. “Shhh, shhh, Twilight, I’m sorry,” she said, her voice soft and angelic once again. “I was merely… surprised. Please, come here,” she said, reaching her hooves out towards Twilight.

Twilight hesitated, noting that even what she thought were stockings was merely a denser portion of the straps criss-crossing much of her body, from which hung silver rings and buckles of all different shapes and sizes. Even in the cups of her hooves were attached what appeared to be fire rubies, intricately carved and faceted to fit tightly against the Princess’s soles without sticking out beyond the hoof.

It was easily the single strangest outfit that Twilight had ever seen. Even so, as if through some spell the Princess made even this look elegant and stately; her glossy alabaster fur, shot through with the faintest hint of flushed pink skin, shined through the gaps in the outfit as it gave her a beautiful patchwork appearance.

“Twilight?” the Princess repeated, her large expressive eyes full of worry as her hooves pulled back a little, hesitating.

Twilight dashed quickly into the embrace, wrapping her hooves as wide around the Princess’s barrel as they would go as she buried her face in the soft fur of the Princess’s (mostly) bare stomach.

“I’m sorry, Princess Celestia,” she sniffled as large, strong hooves held her tight. “I just… I still can’t find out what to feed Spike, and he was crying, and I couldn’t sleep, and I thought….”

“Shh, shh,” Princess Celestia repeated, rubbing Twilight’s back softly in small circles. “It’s alright, My Faithful Student. It’s alright to be worried about him. I promise that we’ll look into it further first thing in the morning, both of us. For now, we should just try to relax. We’ve both had a very stressful night.”

Twilight felt her own breathing calm as the Princess held her quietly for a time, the tension seeming to melt from her back. Wiping her eyes with one hoof, Twilight looked down between Princess Celestia’s still-spread hind legs.

The first odd thing she noticed were the piercings. Princess Celestia had full, smooth and jiggly udders, pale pink and nearly hairless. They had always appeared a bit big and swollen for a mare that wasn’t lactating, but other than that they had always looked perfectly normal, from the first time Twilight had met the Princess and studied them until now.

Now, though. Now they were dark pink and flushed, the nipples standing rigidly erect in a way that Twilight had never seen before. More rings were there, this time passing through the nipples themselves and attached to thin silver chains that were themselves attached to ice sapphires, the whole contrivance pulling the poor teats down toward the floor.

…And the sapphires themselves were not resting on the floor, Twilight noted. They seemed to be laying on something quite a few centimeters off of the pillow, just sort of hovering there between the Princess’s thick, toned thighs.

And then Twilight noticed the two sizable, ovoid depressions in the pillow below the sapphires.

And then she noticed the smell. “Smell,” hardly even seemed to describe it; it hung thick and heavy in the air, overpowering the slight tinge of sweat. It didn’t smell “bad,” but it definitely smelled different, and seemed to almost burn in Twilight’s nostrils, getting her heart pumping and her thoughts dulled, like some kind of… psychoactive.

Subtly sniffing the air a bit, she determined the scent to come chiefly from Princess Celestia’s hooves, in-between her hind legs, and from her underbelly. In fact, looking closely Twilight noticed a thin sheen of something far more viscous than sweat splattered across the otherwise-pristine fur. Noting that the Princess always acted a bit uncomfortable when Twilight investigated her unique alicorn body in the past, she was very slow and careful as she leaned forward and took a deep whiff of the foreign substance.

…Blinking her eyes a bit muzzily, she made a mental note that this was definitely the source of the mysterious odor. Afraid that Princess Celestia would notice her and stop her, Twilight quickly darted out her tongue and ran it lightly over a patch of fur.

…Smacking her lips a bit, and carefully running the fluid over different parts of her tongue to activate different taste buds, Twilight noted that despite the clear salt content this was definitely not sweat. Twilight knew what sweat tasted like, and that was not it.

It was an extremely powerful and unique taste, slightly bitter and more sweet, with perhaps the vaguest hints of some of the tea blends that the Princess favored. It didn’t really taste like something a pony would normally want to ingest… but then, ponies ingested all kinds of weird things in different cultures, and it definitely didn’t taste poisonous. If she had to describe it, it would be an “acquired taste,” one that she at least didn’t particularly mind the thought of acquiring.

Rubbing Princess Celestia’s belly the same way her own back was being rubbed, Twilight tried to imagine where it could have come from. Was it some kind of exotic drink that the Princess had spilled on herself, or perhaps an ointment? Neither really explained well the odd locations of the liquid, including, apparently, between her legs. Was it some kind of special substance that was only secreted by alicorns? Princess Celestia had assured Twilight that her biology was entirely normal beyond the additional size and appendages, but the little filly was still of the scientific opinion that alicorns were a different offshoot of ponies entirely, rather than simply some kind of genetic amalgamation of the other three.

Sensing that the answer to this mystery was close, Twilight thought back on what the Princess had been doing when Twilight first entered the room. She was dressed in this very odd outfit, alone in her quarters, illustrating all the typical signs of heavy exertion while she seemed to wrestle with a snake… thing… between her legs. It had been reasonably long, pale in color, firm enough to retain its shape yet flexible enough to flap and flex when the Princess had been yanking at it.

…Twilight’s eyes slowly widened as a very strange, indeed, almost unfathomable idea occurred to her. She mentally reviewed everything she had read about equine biology and behavior as dots started to connect in head.

“…Princess Celestia?” she called out softly, the side of her face still pressed into the warm, soft underbelly. “Do you have a phallus?”

The gentle rubbing of her back slowed and then stopped. After a few more moments of awkward silence passed, Twilight looked up into her teacher’s face.

Princess Celestia had a distant look in her eyes as she stared into the fire. A slight tilt of her head sent the hanging silver bit tapping against Twilight’s muzzle, still wet with alicorn saliva.

Twilight ignored the potential science involved with that, and asked again, “Princess? Do you have a –“

“Yes, My Faithful Student,” the Princess said, her voice slow and clear as her eyes glittered like amethysts in the firelight. “I have a phallus.”

Twilight couldn’t help herself. She felt her face split wide into a grin, and pulling quickly away from her teacher, she began to pronk.

“Yes!” she cried. “Yes, yes, yes, yes, yes!”

“Twilight,” Princess Celestia called, her voice still studiously neutral. “Why are you so happy that I have a phallus?”

“Because!” Twilight shouted, landing on all fours and facing towards the Princess. “This is my first big discovery! I get to research it, and write my very first research paper on it, and maybe I’ll even get peer-reviewed! I even get to name it, Princess! I’ll call it, um… Penisucus Celestius, or something. I don’t actually know Horse Latin yet.”

Princess Celestia’s wide, powerful wings ruffled quietly at her sides. Her expression, framed as it was by a veritable helmet of leather straps and silver rings, reminded Twilight of some of the old war photos she had seen. “Shell-shocked,” they called it.

“Twilight,” she began after a few moments, “I –“

“And you were masturbating!” Twilight continued, splitting her focus between pondering this new discovery and trying not to prance in place. “Which means it must be fully functional, right? You can maintain an erection, and feel sexual pleasure, and, and….” Twilight’s eyes grew even wider as a new thought slammed into her like the Friendship Express.

Running around in front of the Princess and studying the dual depressions in the pillow for a moment, she began to squeal. “And you have testicles, Princess Celestia! Two of them! And they’re huge!”

The Princess’s hinds drew slightly closer together, those magnificent invisible orbs pressing deeper into the cushiony pillow as if the very thought of Twilight’s science frightened them.

“They are not ‘huge,’ Twilight. Like everything else about me, they are perfectly proportional to my size,” said the Princess, her expression and tone almost pouty.

Twilight studied the depressions more closely, dug up some old statistics in her mental library, and crunched some numbers.

“…They’d still be in at least the ninetieth percentile,” she said finally, firmly. “Even if you were normal-sized. And a stallion.”

Princess Celestia huffed, her face flushing almost as pink as her teats. “Well, Twilight, I suppose as in all things, I am simply blessed.” Studying Twilight almost as hard as Twilight was trying to study her testes, the Princess’s expression softened. “Twilight, please. How do you know so much about… sexual matters?”

“I read,” Twilight said simply, most of her concentration on her magic as she began to probe the area between the alicorn’s hind legs, trying to discover the nature of whatever cloaking spell was keeping her from her prize.

“And…” the Princess continued, looking so uncharacteristically hesitant that it temporarily broke Twilight’s concentration. “…Are most children your age these days also so openly curious and… forward regarding sex?”

Twilight shrugged. “I guess so, Princess? My dad tried to give me “the talk” a while ago, even though Mom said that I was too young, but I ended up telling him a bunch of things that he didn’t know. He seemed kind of upset, though, so I didn’t really talk about it after that.”

She looked up into the Princess’s eyes hopefully. “But I can talk about it with you, right, Princess? You said I could tell you anything.”

Princess Celestia blinked slowly. “…Of course. You are my faithful student, after all. It’s just… sometimes social mores change rather quickly for me. It’s been a long, long time since I could display my full gender in public without causing my little ponies undue stress… and longer still since children were permitted to even acknowledge sex. I’m afraid that I can be a bit slow to adjust, at times….”

“Does that mean that you’ll show them to me!?” Twilight asked, her grin starting to grow again.

“Twilight, I’m sorry –“

Twilight’s grin quickly faded, and her ears drooped.

The Princess faltered, but then continued, “- I’m sorry, but I cannot allow you to publish any papers, at least until I feel that the public is ready to accept my… full nature, once more. In fact….”

Princess Celestia looked over her strapped and pierced body for a few moments, her expression beginning to look as distressed as Twilight had ever seen her.

“In fact, I need you to promise me that you won’t tell anypony about anything you’ve seen here tonight. I’m so sorry, Twilight, but I’m afraid that if ponies learned about my… private life, they would likely do something we would all regret. I can weather a few years or decades of embarrassment, but I worry for you and your family.”

She tilted her head, her voice soft and pleading. “Can you do that for me, Twilight? Can you promise that you will never, ever tell a soul about any of this without my express permission?”

Twilight studied the floor for a few moments as she considered the Princess’s words. It was hard to imagine anypony getting upset about simple biology or sexuality… but then, Twilight wasn’t always the best judge of other ponies or their thought processes. One of the best parts of being the Princess’s student and living here in the castle was that she got to get away from all the other kids and their annoying epithets of “nerd,” “geek,” “dork,” and the like. She didn’t want to think what adults would do if they became convinced she was a nerd.

Looking back into her teacher’s eyes, she asked slowly, “…Does this mean that I still get to study them? If I promise to keep it a secret?”

Princess Celestia hesitated a moment before nodding. “Of course. You’ve already seen and know so much, I cannot imagine what good it would do to deny you your curiosity at this point.”

“And you’ll let me take notes?” Twilight continued, levitating her notepad and pencil from where she had dropped them, a bit of enthusiasm creeping back into her voice.

“…Yes. As long as you promise me that you will keep them strictly to yourself, and take the appropriate measures to hide them from anypony else.” Celestia nodded, silver clinking against silver softly. “I trust you.”

Twilight Sparkle felt her chest swell with pride. Even her own family didn’t take her seriously much of the time, and here was Princess Celestia, the most powerful and beautiful and intelligent pony in the world, a superior lifeform even, telling Twilight that she trusted her.

“I won’t let you down, Princess,” she said solemnly. “I promise!”

There were a few moments of apprehensive silence between them before Princess Celestia took a deep, deep breath, until Twilight thought she could see the alicorn’s ribcage under her fur… and then she slowly exhaled, her horn beginning to glow as she did so.

Radiant golden magic spilled across the area between her legs and below her teats as slowly something truly magnificent came into view.

Swollen. Soft. Ninetieth percentile. These were the words that came to mind as Twilight gazed upon the Secret Royal Genitals.

She couldn’t really see the princess’s penis as it was fully receded inside her silky living sheath. But her balls were a pink sweet and round, the Princess with her widespread wings looking like nothing so much as a majestic bird resting on her clutch. Or perhaps they were really the Royal Family Jewels, hidden where no thief would think to look, their sac almost looking too small for the priceless gems.

As Twilight watched, the eggs seemed to quiver in their home and pull back into the Princess’s body slightly, as if they were afraid of her scrutiny. She noticed that the Princess was still looking at her, slender muzzle etched with worry.

Twilight let her happiness shine through in a wide smile. “They’re beautiful, Princess! Isn’t it wonderful that most mammals keep them outside the body? It’s like they’re meant to be right where females can see how vigorous and virile you are!”

The Princess blushed, the thin fur of her cheeks unable to conceal the pink underneath even as her sheath plumped below. Twilight smiled and continued, “I read in one of my brother’s magazines that your vulva is considered the standard of female beauty in ponies, and that many stallions consider it a rite of passage to attend the Summer Sun Celebration just to catch a glimpse of it. Can you imagine if it were the same with your testicles and mares? Your sexual desirability profile could finally edge into 100%!”

Princess Celestia was breathing harder again even as her divine member peeked its head out like a snake from its den. Twilight gasped as the organ began to slowly swell to life in front of her; even barely aroused it was already thicker around than Twilight’s leg, thin, viscous pre-ejaculate oozing eagerly from the tip.

She had to see the Princess at full erection. In the name of science, she had to.

She gave her most winning smile. “Princess, could you please resume masturbating? I’ve never seen a stallion masturbate before, so I’ll just study your technique.”

“Twilight, I….” The Princess paused for a moment, her gaze looking a little… unfocused. “…Even given the circumstances, I don’t think that –“

Twilight let her face go slack, widened her eyes, and gave her bottom lip just a little bit of tremble. She had been assured many times that she was an instinctively cute little filly, but why leave such things up to instinct?

Princess Celestia gave a half-hearted chuckle, her face flushing nearly as pink as her genitals. “…I must admit, Twilight, this is a first. I don’t get to say that very often anymore.”

Closing her eyes, the Princess reached down, her large, leather-trimmed hooves settling around the sides of her wrinkled sheath. She slowly pressed in and began working her hooves in circles. Her shaft gave an eager little jump, flopping over to the side.

Twilight studied the Princess’s methods. After something like a minute had passed with little further progress, she frowned.

“Is it supposed to take this long, Princess? I thought healthy males were supposed to achieve full erection much faster.”

Princess Celestia gave another breathy chuckle. “I’m sorry, Twilight. It’s been many years since I was watched like this. I’m a bit nervous.”

…Ignoring for the moment the thought that her mentor and ruler could be “nervous,” Twilight noticed something… lacking in Princess Celestia’s technique.

“What about those?” she asked, cautiously walking closer to the action. “Are those sexually sensitive too, or do they hurt when you touch them?”

The Princess opened her eyes again and looked down at her sagging eggs. “I think it varies depending on the stallion, Twilight, but I… very much like them to be touched.” She gave a bit of a wry smile. “Trust me, if I had more than two hooves that could reach, I would not leave them unattended.”

Twilight hummed in thought. She had always sort of thought it would be painful to have your gonads touched like that – she imagined if her kidneys or ovaries were just hanging out, it would be stimulating in all the wrong kind of ways to have them stroked – but then, testes were by definition the most masculine of organs. Like her brother they were large, brave, and very, very fun.

Reaching out one hoof, Twilight rested it gently on the swollen egg. The flesh yielded slightly under her touch, the organ warm, almost hot to the touch; she thought she could feel the wriggling sperm shifting under her caress. The Princess’s Purse tickled her frog with its bumpy little hair follicles as she slowly moved her hoof about, observing the way the crown jewels shifted just beneath the almost transparently-thin skin.

Gently rolling her hoof under the egg, she lifted it up, eyes widening at the incredible heft, the grapefruit almost too heavy for her to lift without the aid of magic. As her gaze traced the network of veins in the elastic sac, she marveled at the happy sagging nature of it, at how it had cradled its precious burden for thousands of years without stretching halfway to the ground.

She tried imagining what the Princess must look like flying, running, and even dancing with these things dancing with her. The room’s subjective temperature elevated for some reason.

Reminding herself that science involved using all of one’s senses, Twilight leaned forward and took a deep breath. A heavy, strong scent that she was quickly coming to associate with masculinity filled her nostrils; the increasingly familiar tang of semen seemed to expand into the vacant recesses of her mind, gradually pushing out other thoughts, and she could almost imagine that it was from the bloated balls themselves rather than the dribbling shaft above.

Acting on what felt like instinct, Twilight knelt down, extending her tongue and touching it to the bottom curve of the sac. Running it up the smooth, stretched pouch, the powerful “taste” of musk mixed with the pleasant taste of the Princess’s salty skin; she almost thought she could feel the gentle slosh of Celestia’s seed as she began to lap at the pungent flesh –

She paused as a thin string of viscous liquid touched the tip of her muzzle. Looking up, she saw the Princess’s Scepter throbbing at full erection above her, drooling pre-ejaculate from the nearly-flaring tip as the Princess’s elegant face stared at her like a frightened doe from behind it.

“…Twilight?” she asked breathily. “What are you doing?”

Twilight blinked up at her. Levitating over her notepad, she quickly began scribbling notes.

“…I see,” said the Princess after a few moments, her expression slowly starting to morph into a smile. “I suppose it would be cruel of me to deny my faithful student her science….”

Smiling, Twilight set the notepad aside while licking the liquid off her nose, savoring the Princess’s flavor. Pleased that her mentor was finally beginning to shed her old-fashioned propriety, and that her body was finally responding with a healthy erection, Twilight decided to continue her current avenue of experimentation as she took as much of one of Celestia’s testicles into her mouth as she could, suckling on the warm egg as she began kneading it with her hooves. Scenes of calves nuzzling and licking their mothers’ udders to encourage milk production came to mind, the thought comforting to her.

Moving her muzzle between the two globes, she began digging deeper into the warm pouch, licking and nibbling the leathery skin as she pressed in as far as she could go. As the royal flesh almost seemed to swallow her, the living jewels gently welcoming her in, she finally met a hot, rigid resistance, and realized that she had found the hidden root of the Princess’s shaft.

Encouraged by her mentor’s soft feminine gasp, Twilight nuzzled the warm root, the shaft throbbing with every strong beat of the Princess’s heart. There was another slow oscillation, a jerking movement that bounced the heavy balls softly against her cheeks.

“Princess?” Twilight said, her voice vibrating the sac around her. “Could you please stop masturbating for a minute? I’m trying to measure your heartbeat.”

The Princess audibly swallowed. “I’m not sure I can, Twilight, I’m… close.”

Twilight used her hooves to firmly knead the hard-working creameries on either side of her head, giving them encouragement in the face of their impending orgasm as she looked up. Stockinged hooves slicked up and down the towering pink shaft, its sides shining as more pre-seed almost poured from the flaring tip.

Reluctantly pulling herself away from her prize, Twilight pouted. “But… Princess! I’ve hardly had a chance to study your penis yet! How am I supposed to do that if you’re stuck in the middle of your refractory period?”

Celestia’s flush and blushes had blurred together into a perpetual rosy hue from the tip of her cock to the tip of her nose as she said, “Despite my age, Twilight, I am still a very active male, I assure you….”

Twilight’s lower lip trembled.

“…And yet, I find the idea of ‘edging’ appealing,” she continued, the silver buckles on her facemask tinkling as she smiled. “What would you like me to do instead?”

Twilight frowned at the problem towering above her. While she might have been able to study a properly sized stallion cock, Princess Celestia’s alicornhood was more proportional to her pendulous sac in size. Throbbing gently between her pierced teats, the tip bounced against the distant matted fur of her chest.

Twilight’s nose wrinkled. “How do you even mate with that thing, Princess? I’m pretty sure it’s well beyond the length of the average mare’s vagina….”

The Princess looked away and cleared her throat. “Well, Twilight, while I always try to emulate Generosity in the bedroom as well as in the rest of my life, I’m afraid that sexually I’ve always been more of a… taker than a giver.”

Twilight took a moment to parse the Princess’s sentence, and then cocked her head to the side. “So… how deep is your vagina?”

The Princess seemed to think about that for a moment, the aforementioned mare-mater beginning to slowly soften as it slumped lazily against her belly. Finally, she sighed.

“My Faithful Student, I won’t lie to you. Most stallions find my female sex to be a bit too voluminous for their satisfaction, and in this age of my life at least, I prefer a more….” She lifted and stared at her forelegs, the silver rings tapping softly against the faux-leather. “…Relaxed, even submissive approach. Down through recent centuries, most of my beaus and I reached an understanding that my vagina may not be the best place for us to express our love for each other.”

“…So fellatio, then?” Twilight studied her mentor’s soft lips; moist, hot maw; and long, delicate throat. Her subjective temperature wasn’t getting any cooler.

Celestia sighed. “Anal sex, Twilight. Stallions tend to find my anus much tighter, more stimulating, more responsive, more intimate, and gives them a greater sense of… control.” She gave Twilight an uneasy, yet sincere smile. “Despite our differences in position and physical stature, when a male takes me under the tail it lets him feel more like a stallion, and me more like a mare. I’ve come to enjoy it; yes, even to expect it.”

Twilight blinked and thought about the strange concept for a moment, a style of mating that she hadn’t read about before. “So… can I watch?”

“…No, Twilight.”

Twilight pouted. “Well, I can’t study that,” she said, pointing at the Princess’s enormous phallus as it slowly shrunk back into its sheath, “from down here. Would you please stand up, Princess? I think I can study the whole thing better if I’m under you.”

“Of course, My Faithful Student,” Celestia states firmly yet with a smile, as if she’s making some grand pronouncement before the court. With a stately gracefulness that belied her age and stature, the great white alicorn shifted smoothly to her hooves, silver tinkling together as she stretched before the fireplace, the flame’s light flickering across her leather-bound face.

Her heavy solar globes were still swaying between her thighs, flushed a healthy dark pink as Twilight buried her face between them, nuzzling into their warmth as she tried to encourage the overstretched sac to remain brave and loose. The Princess’s heady scent surrounded her again, and she lapped at the secret flesh, enjoying the powerful taste she was quickly coming to associate with royalty.

“Twilight!” Princess Celestia gasped. “Before you continue….” She swallowed audibly. “Before you continue, is there anything else you’d like to study? Once you resume in earnest, I’d rather you not stop until we’re both fully satisfied….”

Reluctantly removing herself from her mentor’s testicular embrace, Twilight shivered as her head touched one of the ice sapphires. Following the attached delicate silver chain, the little purple filly bravely lapped at the alicorn’s cool teats before taking one into her mouth, suckling gently on the stiff flesh. She wondered if cold was somehow pleasurable to a pony’s nipples, before concluding with a grave thirst and disappointment that mares lactated during such a brief period in their lives.

Twilight switched her gaze to the alicorn’s third teat practically staring at her from within its fleshy home, dribbling a nutritionally-rich milky fluid onto the floor.

Soon she promised it silently as she let the piercing between her teeth free with a pop.

Taking a few steps back to study the mighty alicorn properly, she once more noticed the dangling bit hanging next to the long, lightly-panting muzzle. Reasoning that excessive loud respiration could only hinder the scientific method, she took the silver piece in her magic and gently inserted it into her Princess’s mouth.

Celestia’s eyes widened, and it was unclear whether she opened her mouth in surprise or obedience as Twilight found the interdental space and secured the bit firmly in place. Seeing the long, moist pink tongue therein rubbing and shifting firmly against the intruder, Twilight resolved to keep it in place by closing the Princess’s muzzle around it with her magic and placing the face mask in its natural position once more.

It took her a minute to work out the complex system of straps and rings and buckles, but when she was done the Princess was once more bundled securely, the perfectly-fitted faux-leather covering all but her flared nostrils and flushed, erect ears.

…In fact, after a moment more of careful study, Twilight pinned the ears carefully back against her mentor’s head and secured them with thick, padded leather cups. With those out of the way, there was no way for the Princess to express further disquiet at any of Twilight’s reasonable scientific inquiries….

…Save for her resplendent wings, shining almost like a swan’s in flight as they were held stiffly erect at the alicorn’s sides. Studying their perfect blend of powerful, bunched muscles; soft down, almost glittering in the firelight; and singularly long, graceful feathers, any one of which would fetch a hefty price at auction, Twilight wasn’t surprised that she had not paid them much mind before now. Being a unicorn herself, she wasn’t used to thinking in terms of pegasus body language, a deficiency that she resolved to correct thoroughly in the future.

Using a bit more force than she had with her mentor’s head, she was still careful not to misalign a single feather as she pushed them into their proper resting pose on either side of the saddle, waiting for them to relax before she swiftly settled two much-larger cups against them, securing the straps much faster now that she had a hang for the process.

Also, while she had several theories as to the purpose of the ensemble in general, she resolved to ask the Princess as to the purpose of the saddle and stirrups in particular once her investigations were over. While she was familiar with equine tack, these were shaped a bit oddly, with the rear of the saddle sloping smoothly into the alicorn’s back and the front featuring a padded u-shape similar to the place a pony would place his head on a masseuse’s bench; the whole assemblage was also placed oddly far back towards the royal hindquarters. She wondered if ponies would ride the Princess before or after they copulated.

Before she could explore the concept further, however, Twilight’s roving eye noticed further distractions. The Princess’s legs, standing like sculpted, living pillars on the soft pillow beneath, seemed determined to make up for the rest of the alicorn’s constriction with their restless shifting and stamping. Feeling her inner completionist taking over, she resolved to first satisfy a bit of curiosity that had been bothering her since she first discovered the Princess masturbating.

Approaching Princess’s hind leg carefully, not giving the blind, deaf, and mute alicorn the chance to accidentally kick her, she imitated the farriers she had seen as she encouraged Celestia to lift up her foot. Holding the leather-sheathed hoof carefully in the air, she studied the inset fire ruby. It looked like it was cut to fit perfectly in the cup of the Princess’s hoof, perhaps to even press up gently and massage her frog as she walked. Still, it seemed like a bit of a waste of a beautiful gemstone for a place that most ponies would never see, and Twilight knew that her mentor held distaste for excessive spectacle and gaudiness.

Probing it gently with her magic, Twilight blinked in surprise as she felt something within the gemstone activate, and similar to the ice sapphires ornamenting the Princess’s teats, it seemed to shine with its own inner light. The Princess snuffled heavily in her mask as Twilight felt the stone radiate a pleasant heat.

A sense of organization and efficiency taking over, Twilight quickly made her way to each of the Princess’s other three hooves, activating their associated fire rubies in the name of science. This had the unfortunate side effect of causing the alicorn to begin wiggling and shifting her hooves ceaselessly as she pressed them into the pillow, not in pain as Twilight initially feared but in a seeming attempt to stimulate herself further.

As Twilight was beginning to expect, a solution soon presented itself in the form of slender silver bars hanging from Celestia’s heaving flanks. It only took a moment to identify their use, detach them, and affix them anew to corresponding rings about the Princess’s fetlocks.

Stepping back once more, the industrious little filly admired her hoofwork. The Princess’s hooves were now set nicely apart and locked firmly in place by the four sparkling bars, one between each pair. It was now thoroughly impossible for her mentor to move any part of her body in a way that might impede Twilight’s further –

The Princess’s dock began waving wildly about, almost mocking the little scientist.

“Ugh,” Twilight uttered aloud, rolling her eyes in a way that she never would have dared to do had the Princess been less sensory-deprived. She moved around to the rear of the goddess-horse and paused, taking in the sight for a moment.

Even as young as she was, Twilight had seen her fair share of vulvas, and generally couldn’t understand stallions’ seeming fascination with the subject. Most appeared as a simple wrinkled, fleshy slit jutting out from beneath the mare’s anus. And while she would be the first to affirm the Princess’s as the most beautiful and glorious vulva of all, she had never seen it quite like this before.

The royal cunt, normally the same light pink as the rest of her exposed skin, had flushed almost red with arousal as the lips had swollen wide, exposing the pink vagina normally hidden inside. Even the Princess’s clitoris, a secretive, plump organ that put the sexual girth of many stallions to shame, was winking out aggressively, almost flirtatiously.

And with good reason. Around the vagina was a circle of rings jutting out from otherwise-invisible piercings in the surrounding lips; despite what Celestia had said earlier, these seemed designed to welcome in and massage a stallion’s cock as he had relations with her in the traditional manner. The capstone of the piercing love-circle was what looked almost like a wedding band, the thick silver ring pierced straight her clitoris while a mounted already-blazing fire ruby seemed to ride the winking flesh, the stone seemingly sized and cut to stimulate both partners during intercourse. Twilight almost imagined she could see steam rising as a thin stream of whitish lubrication oozed from the vaginal opening, hugging the clit gently on its journey to a wet spot on the pillow below.

Twilight’s very innocence raised its eyebrows as she realized that that gemstone must have been going hard the entire time. The Princess was clearly very, very experienced.

Taking in a deep breath of the pussy’s unique aroma – very different from that of the male genitals dangling neglected not far beneath, but still pleasant and even exciting in its own way – her gaze finally traveled to what, according to the Princess, was the true prize above.

Some of her brother’s magazines had speculated on the exact nature of the Princess’s royal anus. While an enterprising young stallion could catch glimpses of her cunt at almost any major public event using a telescope, Twilight knew that even the royal guards were unfamiliar with what lay directly underneath the modest ethereal tail. Some of the guards made wild claims about its true nature, boasting within an inconspicuous little filly’s hearing that they had caught sight of it during sudden windstorms or when her tail instinctively raised during estrus, that it gaped unusually wide or puckered unusually tight or, in one case, that she possessed no ordinary anus at all but that her tail actually extended from her rectum in a diaphanous rainbow of divine flatulence.

Twilight, of course, being not only close to her mentor but also attentive and very, very small in comparison, had addressed the rumors scientifically by studying the Princess’s anus in detail and scheduling a presentation before Equestria’s Supreme Council for Military Affairs to inform them that it was, in fact, quite normal overall, barring its abnormally light pink coloration, fastidious cleanliness, and odd habit of clenching and flexing whenever a particularly strong, attractive male had her attention. It also appeared to be a bit looser than normal, but given the Princess’s relative gigantism and Twilight’s (soon to be rectified) inexperience in the matter, she had felt unqualified to judge their monarch’s tailhole as “gaping” or not.

She had wanted to inform the individual guards as well, and even had notes and sketches prepared for that purpose. Unfortunately, they all retired before she had the opportunity. Once she helped Spike through this present crisis she still intended to write a report to the Princess about the military’s excessively high turnover rate.

At the moment Celestia’s anus appeared much as it always did, a perfect, powerful sphincter enveloped by two muscular, yet well-padded cheeks to either side, almost like two crescent moons clasping a treasure between them, the leather straps covering the twin suns even as they seemed to frame and highlight the beautiful, welcoming orifice usually secreted away beneath the Princess’s tail.

And beautiful it was: nestled in the center of the fleshy ring was by far the largest gem yet, one that Twilight couldn’t identify, blazing a purple not unlike Twilight’s own coat. On closer inspection, it was actually a swirling matrix of cobalt and crimson, emanating cold and heat as it shifted more toward one or the other. In fact, Twilight noted that as it turned red the surrounding sphincter seemed to loosen and relax happily, which seemed to drive the magical artifact towards blue again, causing the Princess’s developed, practiced rectum to clench down powerfully on the in the inserted device, rippling and squeezing rhythmically until it began shifting red again. She wondered if the clever design was pressure-activated. That’s how she would have made it.

While Twilight couldn’t see past the smooth, rounded surface, it seemed clear from the way the anal ring bulged and how the visible portion of the stone was held so steady that the actual device extended deep into the royal fundament and was roughly the size and shape of the average stallion’s cock. Considering the possibilities offered by such an invention, Twilight wondered if Celestia ever simply cloaked the device the same way she cloaked her male genitalia as she went about her day-to-day duties. It would not only explain some of the stranger rumors regarding the Celestial ass, it would also provide a means for the Princess to relax and please herself while also training to better accept and please her mates. Somehow, Twilight doubted that most mortal mares were so thoughtful.

Twilight blinked as the Princess’s dock shifted, the aetheric tail flowing coolly across her face and cupping her chin, almost as if it had a life of its own. A possibility that the young scientist had yet to rule out.

Almost as an afterthought, she seized the tail and slipped the whole thing through a corresponding ring on the leather apparatus, securing it while exposing the Princess’s attractive, flirtatious tailhole to the world. Which was as it should be, in Twilight’s opinion.

Backing away from the Princess for what would hopefully be the last time, Twilight inspected her from the tip of her flared nostrils to her jutting, winking clitoris. Every part of the consummate mare was properly bound and stimulated, indistinguishable from a large, anatomically accurate alicorn ponyquin save for the lathered, heaving flanks; the rhythmic motions of her neck as she rocked her body back and forth, seemingly in imitation of thrusting her cock into a mare, or being thrust into; and the almost-sizzling glow of sunflower magic from her horn as she burned magic seemingly without casting any particular spell.

While the respiration was (probably) necessary, Twilight was determined to finish what she started. After a moment’s careful consideration, she determined that if the Princess really wanted to escape, she could probably break free from her bonds without any true struggle.

With that in mind, she took one of the few remaining unused dangly bits on the leather suit, an oversized cold-iron “horn collar” as it was colloquially known, and slowly slid it over the Princess’s extraordinarily long, slender horn, careful not to scruff or scrape the fluted keratin in any way. Rather than protest or struggle, the Princess gave her first full-throated moan in response, which was not at all the normal response to thaumaturgical castigation, but Twilight was getting the impression that, much like Twilight herself, Her Majesty was unusual in more than the obvious ways.

She also clasped and secured a few additional straps, forcing the Princess’s head up and preventing her from moving it, just for good measure.

Satisfied that she had now taken every reasonable incapacitating measure short of sedation, Twilight now honed her sharp and curious attention on the only part of her Princess still capable of any rebellion at all. One most unique and worthy of study.

In point of fact, the aforementioned organ was even while mostly flaccid still flexing powerfully, bouncing her balls in their sac even as the shaft slapped wetly between her teats. It seemed that without any other possible outlet, all of the Princess’s pent-up lust and excitement were being forced into her genitals.

While that wasn’t the worst possible result, Twilight had a different method of egress in mind for Celestia’s lust. She licked her lips as she prepared to tame the Princess’s writhing snake.

Stepping under her mentor’s heaving flanks – not stooping, the Princess being really, truly huge – she quickly examined the lathered, matted fur and ebony straps above her. While no more magical crystals or gemstones presented themselves – other than the pair of ancient, priceless ones dangling right in front of her, of course – she quickly located a set of three large silver rings attached to adjustable straps conspicuously located in a line straight along the anteroposterior axis. Detaching them so that they were hanging freely, she calibrated them so that the one farthest from the Princess’s groin was at Twilight’s eye level.

She then reached out, putting her forefeet around the swollen sheath, taking a moment to admire the leathery flesh that protected the furtive Celestial phallus before she began stroking it firmly, rubbing her tiny hooves back and forth across the hot flesh, trying to encourage the princessly shaft to once more swell out from its home.

Within moments the alicornhood lurched forth as it began to engorge with lust, and it was all Twilight could do to slip it through the first and second rings before it had extended too far. Kneading the rubbery flesh, Twilight felt her own excitement growing with the Princess’s as the cock grew to full erection just as the glans slipped through the third ring, the girth of the scepter straining slightly against the rings and locking it on display. Twilight could finally study the magnificent organ in peace.

And magnificent it was: while perhaps no longer than the largest draft ponies’, it was far thicker than normal, truly a “fifth leg” as they were known. Purple veins bulged through the innervated pink flesh, the medial ring straining mightily against the argent ring just behind it, the pressure in the mare’s balls so great that the head had already begun to flare as it drooled ambrosia onto the pillow below.
Twilight Sparkle conjured her handy-dandy measuring instruments.

Within moments she had various length, width, and circumference assessments, along with temperature readings and sketches. The engorged cock throbbed visibly with every powerful beat of the Princess’s heart, and Twilight wondered why medical personnel went to such trouble to feel the heartbeat in other parts of the body.

Taking an equine scrotal caliper – something she had purchased herself but never had the chance to use, given her parents’ often fillystine attitudes toward science – she found that it was not sufficient to measure alicorn gonads, and made a note to purchase the dragon version next time she received her allowance. She quickly substituted her extra-soft vinyl measuring tape, wrapping it across both the length and breadth of the testicles, the eggs gently rolling up and down in their basket as she did so, presumably a sign of pleasure.

A few quick mental calculations later, and Twilight’s eyes widened.

Quickly removing one of the earmuffs and the mouth cover with her magic, she asked, “Princess? How often do you masturbate?”

Her mentor swallowed before replying, “…Not as often I’d like, My Faithful Student. Perhaps once a week, when times are harmonious.” It was odd that none of the tension in the Princess’s reply came from the bit in her mouth; she had the enunciation skills of an earth pony or pegasus.

“And each ejaculation has to be at least several hundred milligrams, right?” Twilight continued accusatorily.

“…I have always been quite prodigious, yes. Might I ask why this is such a bad thing?”

“And what do you do with the ejaculate?” Twilight continued, even going so far as to ignore a direct inquiry from the Princess.

The Princess’s head jerked slightly, as if she had forgotten that the suit now kept her from even turning her neck. “Why, I magic it down the toilet, of course. Or incinerate it in the sun. It is one of the reasons I have these little sessions in the first place. My body will have its way whether I wish it to or not, and I have not forgotten what it’s like to have to explain soaked sheets to the maids.”

Twilight put her hooves on her head and tried not to hyperventilate. “But Princess, if we assume a mere half liter of production a week, that means that you’ve flushed 26,000 liters of alicorn semen down the tubes in the last millennium alone! Do you know what that means, Princess?”

“Twilight, I don’t –“

“Right now, alligators and rats are drinking 26,000 liters of divine proteins, fructose, vitamins, and minerals! Fish throughout the Equestrian river system are being inundated with 26,000 liters of royal endorphins, estrone, prolactin, oxytocin, and serotonin, giving them an un-earned emotional high! The Scientist’s Guild complains about a lack of government funding while the post-combustion remnants of 26,000 liters of undiscovered alicorn female sex hormones rain down on them from the sun!”

Though her mentor couldn’t see her, Twilight felt her eyes watering all the same. “Semen is one of the most biologically complex and thaumaturgically dense secretions in the natural world, and you’ve just been throwing it in the garbage? Princess, I thought you loved science!”

“I do, Twilight, I do,” the Princess replied, the soothing nature of her words somewhat offset by the urgency in her tone. “I will let you have all of the semen that you desire for your private study, but please, Twilight, either finish what you were doing before or release me. I do not think I can take much more of this –“

It would have been unthinkable before that night to interrupt the Princess, much less muzzle her with fake leather. But Twilight felt a greater call than mere educational fealty.

That call was the near gurgle from the straining orbs, simultaneously dragging their sac low and stretching it tight with the weight of the wriggling sperm therein. The space between Celestia’s thighs seemed hardly sufficient for them as Twilight seized them in her magic.

Enveloping the precious eggs in warmth to replace that of their broodmare above, she lifted them up and separated them out as much as she could in their living pouch, relieving the weight on Celestia’s hindquarters as she began kneading them firmly but gently, trying to stimulate production even as she coaxed the sperm from their nesting place.

Encouraged by the Princess’s deep, almost pained moans, Twilight started squeezing gently back and forth along each swollen testicle, her violet magic seeping into the overburdened sac and seeming to stretch it even further as she undulated her magic rhythmically across them, trying to imitate the heat, pressure, and texture of the bare balls riding in the mouths of mares, suckled firmly as thirsty tongues tried to lick the cream straight out of them.

The swollen udder quivered and sagged with the pressure of Twilight’s magic, Celestia lowing like a cow in heat and straining against her bonds as Twilight moved to the business end of the alicorn’s great teat. Seeing the rounded, partially-flared head and the drooling ring nestled within it, she started by licking around its edge.

The texture was a little coarser and more crevassed than she expected, doubtless intended to roughly and vigorously stimulate a mare’s innermost sex, but the taste was both subtle and powerful in a way that the little filly couldn’t describe. She continued bathing the turgid flesh for a few minutes, ignoring the groans coming from above even as she continued to feed as much magic into the Princess’s sac as she could.

When the curiosity and scent were finally too much for her, Twilight dipped her tongue below the dripping pink head and licked up to the urethra. Though it was little more than lubricant at this stage, the taste was still almost overpowering, seeming to reach into something deep within her female psyche and triggering an animal need that ran from the salty, slimy taste in her mouth and burning masculine scent in her nose through her quivering center to an unusual heat under her tail.

Suddenly she felt thirsty, thirstier than she had ever been, and she gaped her maw as wide as it could go before slipping the entire head into her warm, moist mouth. It felt much easier and more natural than she expected, and her mouth began suckling on the nourishing flesh without her prompting, nursing on the responsive, almost maternal flesh as it began almost spurting alicorn milk against the back of her throat.

She reacted by pressing her tongue against the fat little urethra directly, lapping heavily at the miniature doughnut even as she sucked as hard as she could on the throbbing flesh in her mouth. The cock was as gentle and polite as its mistress, venturing only the mildest bucks against its confines, giving more and more as she took more and more, every few seconds swallowing a small pool of pungent pre-seed and letting its warmth bloom in her stomach.

Just as she began wriggling her muscle into the tight little hole, thrusting in and out as she tried to fuck Celestia’s cock with her tongue, she felt the hefty jewels begin to tug heartily against her magic, the entire purse shrinking as the Princess’s body jealously tried to pull its treasures back into itself. Realizing the danger, Twilight popped the head free of her mouth just as it began to flare in earnest, the glans quickly doubling and more in size as the urethra swelled and jutted out eagerly towards her staring face.

Thinking quickly, Twilight continued to keep pulling on Celestia’s balls as she extended the rest of her magic toward a large, spotless ship-in-a-bottle, likely a gift from some ancient potentate or lover. Leaving the useless ship behind, she teleported the bottle straight in front of the straining cock, unstopping the cork before nestling the mouth against the head, wrapped her hooves around the shaft for extra stability, and released her grip on the now-quivering testicles.

She felt the first pulse before she saw it, the already-adamantine shaft swelling as potent, gooey seed shot out of the tip with almost supranatural force, the bottle nearly jerking out of her thaumaturgical grip even as the Princess’s muffled groans reached a nigh wailing pitch above her. The second, third, and fourth jets were nearly as powerful, semen thick with sperm splashing against the base of the bottle and filling it so quickly that Twilight had to devote more and more magic just to keeping it in the air.

Determined that not one milliliter of alicorn essence would be wasted while she was here to stop it, Twilight began stroking the orgasming shaft as vigorously as she could, milking the Princess’s captive cock as she tried to stimulate it to further and more voluminous orgasm, intent on draining the alicorn’s balls until they were dry and satisfied. With the last vestiges of Twilight’s concentration, she also cast a “Librarian’s Delight” spell on Celestia, muting the monarch’s throaty near-screams to a whisper before she could alert the guards.

The remaining jets quickly began to die off in intensity, the eggs already nestling down in their worn pouch as the alicornhood’s spurts grew gentler and gentler, the milk going from a thick, frothy, creamy white to a more translucent, runny blend. Twilight was just preparing to look for a second container when the squirts became drizzles, the great pink cock looking tired and wrung as it quickly began to soften, shrink, and retract back into its home, drooling a line of watery semen across the pillow below as it did so.

Quickly stopping the bottle up again to preserve freshness and wrapping it in a precisely-modulated warmth spell to maintain sperm health and motility, Twilight then took the liberty of cleaning Celestia’s cock herself, very gently fondling the lighter, happier sac while suckling on the tip of the exposed penis until it was even cleaner and more satisfied than she had found it. Setting the precious bottle off to the side – coming in at a liter if it was an ounce, she noted with awe and satisfaction – the little filly then, and only then, began to unbuckle, unstrap, and unburden her Princess, starting with her barrel and limbs and saving the neglected front end for last.

When at last Celestia’s mouth and face were exposed, she took a few deep breaths, let her gaze wander over Twilight and the bottle with a glazed look, and then slowly sank down into the pillow before the fire, parts of her sweaty, matted white coat laying across the various stains she had made in the fabric. Twilight left in the various gemstones, piercings, and plugs across the soles of her feet, nipples, clitoris, vulva, and anus, partly because she didn’t know how to remove those safely, and partly because she thought her Princess looked more beautiful and content with them in. Even now she could see her mentor’s tailhole clenching firmly, affectionately, rhythmically around its guest, the Princess trying to draw her mate deeper into herself even as she slept.

Giving her regent and teacher one last kiss on the cheek, tasting the salt on her lips as she did so, Twilight gently hefted the bottle and notebook in her magic and made her exit from the royal chambers. She gave the guards outside the doors a thankful nod for protecting Her Majesty’s privacy, not acknowledging their curious stares as she headed down the hallway to her own quarters.

The little filly hadn’t made it far down the darkened hallway before her thoughts turned toward her newest family member, and the warmth in her chest and belly began to be replaced by guilt. Her discovery of the Princess’s fascinating genital pouch had pushed all thoughts of Spike from her mind, despite her responsibility to the little dragon. She had spent what must have been the better part of an hour or more discovering and experimenting and stimulating without so much as considering a solution to her real problem, much less discussing it with her mentor as she had planned. While Spike was sleeping hungry, she had been having the time of her life.

…Twilight was a terrible big sister.

Struggling not to let herself be overwhelmed by tears, she all but dashed into her room and peeked into the basket of her little brother. Dragons were by nature much tougher and less needy than equine foals, especially considering how their parents could often be away enslaving diamond dog colonies or foalnapping lesser princesses for days at a time, but it still relieved her to see the little purple-and-green hatchling was alright, the way he suckled extra hard on his tail in his sleep the only sign that he was still hungry. In fact, the way he dug into the broad tip reminded her nothing so much as how she had been similarly nursing from the Princess just a few minutes before, like a calf at her mother’s teat.

…Twilight slowly turned to stare at the bottle, the warm, viscous, bubbly liquid looking like nothing so much as an extra-large glass of mother’s milk, the contents so alive and infused with solar essence that it almost seemed to burn in her magical grip. Noting her own desperation and the experimental nature of science, Twilight seized a few of the empty milk bottles lying about the room and quickly emptied a portion of the Princess’s gift into each of them.

Without hesitation, she nudged Spike’s tail out of his mouth and put the warm bottle in its place.

Not so much as opening his eyes, the infant dragon took the artificial nipple in his mouth and began sucking hard, his scant cheeks quickly bulging like a chipmunk’s with fluid. Instead of spitting it back up like every time before, however, the babe seemed to take an almost instant liking to the potent alicorn cream, draining the entire bottle in less than a minute. Twilight was quick to replace it with a full one before he could wake up or cry.

Just as Twilight was beginning to worry if she would have to fill more bottles, or if she would even have any of Celestia’s seed left for science at all, Spike abruptly slowed down and burped, his stomach visibly bulging as he seemed to fall back into a deep sleep, still clutching the half-full bottle to his chest. Twilight watched her little brother carefully for several minutes, searching for the slightest hint of an adverse effect. Once she had reassured herself that Spike wouldn’t have an allergic reaction or vomiting, Twilight finally allowed herself to smile, both pleased and not at all surprised that the Princess had managed to solve her problem for her, even without meaning to. The Princess was almost like a mother to the little dragon, after all, and it only seemed right that she should be able to feed hi m like one.

Crawling back into bed and giving Smarty Pants a kiss on the forehead for being so patient with her, Twilight set the big bottle on her dresser while taking the remaining foal-sized one and clutching it to her chest in imitation of Spike. Sipping from the tip, she felt the now-familiar warmth spreading throughout her body and easing her into sleep, the taste of her Princess on her tongue and a smile on her lips.