There's probably a lame speech pun somewhere that would fit.
“Are-are you sure about this, Mistress?” Celestia nervously asked from behind as she followed her sister through the quiet abandoned early morning hallways of the castle.
Celestia almost bumped into the back of Luna as she came to a dead stop in the middle of the hallway and turned around, an irritated expression on her face... “Are you questioning me, whore?”
Celestia avoided her sister's gaze, she stared down at the floor, “No Mistress, I—“
Luna grabbed the collar wrapped around Celestia's neck, interrupting her pet's response. A soft 'yelp' escaped Celestia's mouth as she was pulled forward quickly. The pair's faces were mere inches away from one another. “What is this I have in my grasp?”Luna asked.
“M-m-my-my slave collar, Mistress, I-I-I'm sor—” Celestia stammered out, already realizing her mistake.
Luna tightened her grip and yanked the collar again. “Remind me, slave.” Luna's free hand began to twist and tweak the crescent moon nipple piercings that hung from her slave's tits, eliciting pained gasps. “What are the rules when you put on your slave collar?”
“When wearing my collar, I am to obey Mistress's orders—gasp without question. I am just a simple-minded—gasp cock-sleeve. Questioning my Mistress requires punishment,” Celestia managed to squeak out.
“Good... I was starting to wonder whether your lack of clothing was affecting your brain somehow...” Luna released her grip on her pet. “Your punishment will have to be saved for another time... You've already caused me to waste enough of it reminding you of your place.”
“I'm sorry, Mistress.”
Luna rolled her eyes, turned back around, and swiftly began walking through the halls to their destination, Celestia followed closely behind.
The two sisters had quite a unique dynamic. In the public eye, both were leaders, sharing equal duties in their country's growth and prosperity. Each of them providing their fair share of solutions to political problems within their borders and abroad.
But privately, the two shared a much different bond. One that would most certainly be shunned by the media and most of the population if the secret were to ever be revealed.
Over the years, Celestia discovered that she greatly enjoyed being sexually submissive. Something about giving up control truly stoker the fires of her arousal. For a long time, she believed she was alone in her deviant thoughts, secluded to live out her desires only in her dreams. If not for her sister's ability to walk the dream realm and peer into one particularly intense and vivid submissive dream, she may very well never have found herself in their current relationship.
Aware of the consequences and potential backlash if the knowledge of this were to ever come to light, the pair came to an agreement. Luna would be her elder sister's Mistress and Celestia would submit to her younger sibling in sexual servitude whenever time allowed for it.
At first, things between the two were 'tame' compared to now, but Luna was serious from the start in her new found role as Celestia's Mistress. Celestia's 'training' became a nightly regime, beginning with different toys and restraints she quickly met Luna's expectations. From there, Luna decided to unveil to her sister a spell that she had grown rather fond of, a spell that gave her a fully functioning stallionhood. Over time, Celestia grew to love the growing intensity and depravity Luna showed her. Luna trained Celestia into one of the best submissives she had ever seen. Each one of her holes molded into perfect 'pleasure-sleeves', fitted perfectly for her mistress's cock. Able to contort her body and be restrained in a number of different ways.
Celestia stood motionless atop the small stage placed out on the main balcony of Canterlot Castle. The early morning breeze rolled down and across her body, sending shivers down her spine, causing her nipples to stand erect on her breasts and goosebumps to creep on to her skin. Staring out into the courtyard and the city, she could feel the piercing gaze of her Mistress upon her. She waited for her command.
Luna approached Celestia from behind, pressing her body into her pet's back, she reached around and grabbed a handful of breast, playing with its nipple between her fingers. Her other free hand groped her favorite asset her pet had, the two thick mounds of flesh that made up Celestia's rear.
Celestia tried to ignore her Mistress's touch, but a short gasp and soft moan escaping her mouth betrayed her. She could feel Luna's prick pressing into the small of her back as she stood there, gradually becoming putty beneath her Mistress's hands. Her pussy began to dampen, small droplets of her arousal trickled down her inner thighs. Her moans gradually became louder and more desperate.
In an instant, all that pleasure was gone. Luna retreated back a short distance, content to watch her slave quiver and squirm for a moment, Celestia clearly wanting the pleasure to return.
“Assume position two, Pet,” Luna said.
“Yes, Mistress.”
Celestia complied, her body still quaking. She spread her legs wide, bent over at the waist, locked her legs straight, and grasped each ankle in her hand. Her neck craned upward, facing forward, making sure she could only look straight ahead. Her large breasts dangled freely from her chest, her pussy and ass on full display for her Mistress.
Luna's horn glowed, the sound of magic filled their ears, a low rhythmic hum as she opened up a special 'storage rift' next to her. She reached into the rift and pulled out one of her 'prized' training tools. A wireless remote controlled vibrating dildo that was a perfect replica to her own stallionhood.
Celestia diligently held her pose, she felt herself leaking onto the floor below, her mistress had done quite a number on her. She heard the footsteps of her mistress approach her again, uncertain about what to expect. She could feel Luna's presence behind her, her mistress's fingertips touched the back of her neck, playfully touching her naked skin, they slowly trailed downward along her back and made their journey down her legs, tracing her curves.
Luna hummed while caressing her pet's body. “You truly do have a beautiful body, curves in all the right places, sometimes I have to stop, stare, and marvel,” she said.
“Th-th-Thank you, Mistress,” Celestia struggled to say.
Luna's fingers started back up along Celestia's legs and toward her inner thighs, landing on Celestia's sopping cunt. Two fingers spread her folds apart and began to tease and play with her poor pet's leaking sex, quickly becoming drenched in her juices. Luna pulled her hand away and brought it up in front of Celestia's face. She heard the distinct sound of her pet inhaling deeply as she wafted the scent from her fingers into Celestia's nostrils. “Open wide.”
Celestia's mouth opened with an audible 'ah', her mistress inserted her fingers inside Celestia's hungry mouth. Her mouth clamped down on Luna's digits and began to dutifully suck and lap them clean, savoring the salty, tangy taste and the thick, rich texture of her own juices.
Luna pulled her fingers free of Celestia's mouth, wiping them off on her morning gown, she looked down and watched her tremble, visibly shaking from her relentless teasing. Luna floated her 'training tool over within her magic, grabbing it out the air, she began to slide it between her pet's nethers, getting it slick and well lubricated as it sent sensations of pleasure through Celestia's body every time it grazed her clit. Luna barely prodded Celestia's marehood, sliding the head of the dildo in, a gasp escaped Celestia's mouth. Luna pulled back and slide the toy between the crack of her pet's ass. Slowly alternating between both holes, she teased Celestia even more.
Celestia's body had a visible sheen, coated in a fresh thin layer of sweat, her ragged breaths caused her chest to heave up and down. Her pussy clenched tightly down every time her mistress inserted a small fraction of the toy's length, trying to hold it in place each time her mistress pulled it free. Her leg muscles strained from holding her position for so long.
Finally, her mistress spoke. “Tell me, pet which hole should this toy grace with its presence, hmm? ”
“Whichever one my mistress deems most worthy.”
Celestia knew she did not really have a choice, she was trained to enjoy any hole her mistress chose.
Without any warning, she felt her pussy swiftly become filled, the entirety of the toy was powerfully thrust inside her, the dildo's tip rested right up against her cervix. A loud cry of pleasure was ripped from her mouth, her legs nearly gave out on her. A flash of white blinded her vision as she felt the soft vibrations begin from the toy—turned on 'low' by the remote her mistress was holding.
“On your knees, pet, it's time to get you ready for later today,” Luna commanded.
Celestia dropped to her knees, her legs thankful for the small respite they received, she was careful to make sure that her mistress's toy did not fall out as she sat on her heels. Celestia heard more things being pulled from Luna's rift, it finally closed with a 'clap', her mistress's footsteps became louder.
“Arms behind you're back,” Luna watched her pet comply, bringing both arms behind her back and stacking her forearms on top of each other—just how she had been trained. Luna wrapped a thick leather strap tightly around Celestia's forearms, locking them together. Next came leg restraints that wrapped around her thigh and ankle, connected by a sturdy bar for each leg, they made certain that Celestia would be unable to change position.
Only a few more items remained as Luna stood in front of her pet, she placed her hand underneath Celestia's chin and brought the bound mare's face up to see the ring gag dangling from her hand. Celestia took the hint, opening her mouth, Luna placed the gag securely inside Celestia's mouth and fastened the strap tightly behind the head.
“One more thing, pet.” Luna said, a small sly grin on her face, she held a gold magic-nullifying ring in her hand. “Don't want any magical impulses interrupting today's speech.” Held between her thumb and index finger she lowered the ring down on to Celestia's horn until it was snugly secured near the base of her horn.
Celestia let out a low groan as she felt her magic cut off from her. Drool slowly pooled in her mouth, it trickled out past the gag and down her chin. She tested out her bonds, finding there was little to no give.
“Today's speech is going to be very enjoyable, we're going to find out just how far you've come along in your training.”
Celestia was shrouded in darkness, the only source of light coming from a perfectly round hole in front of her that her ring gagged mouth was forced to nearly cover, a small chain connected to her collar forced her to hunch forward and kept her from moving her mouth away. For the time being, she was trapped inside a hollowed-out false bottom of a wooden podium that stood front and center on the stage where today's State of Equestria Address would take place. Forced into a kneeling position, locked there by a multitude of restraints. Luckily for her, she wasn't claustrophobic.
She squirmed in place, the faint buzzing in her nethers taunting her. The vibrating replica of her Mistress's cock filled her marehood, the flames of her arousal were stoked but did nothing more than torment her as she could not find release from the minimal pleasure provided. Her struggling was in vain, her knees were up against one end of the wooden podium while her feet could just barely push against the other wall.
Only one other pony knew of her whereabouts, the one who put her here in the first place, her Mistress and sister, Luna.
For the past hour, she had been alone with just her thoughts and the annoyingly wonderful yet tormenting buzz pleasuring her loins. She started to hear the murmuring of a crowd gathering, signaling to her that she did not have much longer to wait until her mistress returned to give her speech and received plenty of oral pleasure while addressing the populace. Normally it was her own duty to speak to the nation, but she was confident her mistress could explain away her absence.
Celestia moaned, the thought of her mistress's cock stuffed down her throat, discreetly pleasing her in front of everypony, heightened her arousal. The puddle of her own juices she was stuck kneeling in became larger. Saliva ran out of her mouth, down her chin, and on to her breasts—her maw was more than ready for her mistress's rod.
Fanfare began to play, the crowd roared with applause, Celestia could hear her mistress step up to the podium, the shuffling of papers above her, and an audible sigh as she felt her mouth filled with her mistress's length. It prodded the back of her throat, she relaxed her throat, allowing the wonderful thickness to slide deep into her throat. The collar around her neck tightened as her throat expanded from taking in such an amazing stallionhood. Celestia breathed through her nostrils, a thick and pungent mixture of her mistress's and her own scents filled her nose—a pleasant lightheaded feeling hit her. She constricted her throat, doing her best to give her mistress an amazing cock massage, her tongue worked hard, licking and lapping near the base while humming.
“Thank you, everypony for joining me here today. I know all of you are wondering where my beloved sister could be...” Luna's words rang out loudly over the speakers while Celestia continued to pleasure the cock stuffed in her throat. “Unfortunately, other important have her tied up at the moment... She wishes she could be here but has graciously entrusted me to give her speech on her behalf.”
The crowd gave a loud cheer, seemingly happy with the excuse Luna had given. “Without any further ado, let me begin.”
Celestia squealed, the vibrations coming from her sex nearly doubled in intensity. The pressure in her stomach built up even more, edging closer to a possible climax. Her eyes blurred and fluttered for a brief moment, her mind losing focus.
The cock in her throat throbbed, obviously enjoying the pleasure give by her squeal. A spurt of precum dripped down her throat, warmly landing in her stomach. She continued to swallow, using her throat and tongue, her mistress's cock twitched in her tight, bulging throat. The sounds of a thorough throat fucking were drowned out by Luna's speech, although if you listened carefully you could hear a stifled grunt every so often.
Without warning, Luna's cock erupted, sending its first load directly into Celestia's gullet. She swallowed as quickly as she could, intent on making sure not a drop of seed was spilled from her mouth or throat. After several large gulps the onslaught of cum trickled down to a halt, Celestia's stomach sloshed with cum, a sense of fullness washed over her.
Her mistress's cock softened and retreated a few inches out of her throat, just enough to allow her some sort of reprieve as she panted and tried to gather her breath. The moment was short-lived, her breath was taken away in an instant. The vibration motors inside the dildo filling her cunt revved to their highest setting. An earthquake of pleasure rocked Celestia's body, she trembled in place, her eyes rolled up into her skull, her muffled gurgling scream of rapture reverberated through the member in her throat.
Celestia's marecum gushed out in spurts passed her spasming marehood, magic sparked from her horn, but the ring she wore quickly dashed any attempts of magic being used. Her head tried to pull away, the pleasure became overwhelming, she was quickly reminded by the short leash holding her neck and mouth in place that her head was stuck and the cock in her throat wasn't going anywhere until her mistress's speech was over.
Celestia was lost in bliss when her mistress's cock finally pulled itself from her mouth with a loud pop. She groaned, her normally toned and flat stomach now bulging and sloshing with all the cum her mistress had bestowed upon her. Her ears twitched when they picked up the sound of the crowd cheering and her mistress thanking everypony for attending.
The buzzing in her nethers stopped, finally a break from the sensory overload that had been wracking her body. Her eyes were heavy with fatigue, they closed shut as she slowly passed out.