Chapter 1
“I'm so sorry, Rainbow Dash,” said Fluttershy, “But my dear darling sweethearts gave me quite a workout today. I can't be much of a host until I take a quick shower, I hope that's all right.”
Dash eyed up Fluttershy. From the look of her, her animals - her “dear darling sweethearts,” to hear her tell it - had put her through hell. Her mane was woven with leaves and brambles, her pants were muddy up to mid-thigh, and her white shirt was soaked through with sweat - which gave Dash an unusually close look at the yellow pegasus’ enormous, braless tits. Even after a rough day of wrangling animals, Fluttershy had a body that other mares - Dash included - openly envied.
“Sure, take as long as you need,” said Dash, taking a seat on Fluttershy's couch. “Don't rush your shower on my account, Flutters.”
“Ah, thanks,” said Fluttershy. “I'll make some tea when I get out, but in the meantime, help yourself to whatever's in the kitchen.”
Fluttershy slouched off towards the bathroom, and Dash leaned her head to the side, peering into Fluttershy’s kitchen. She could use a snack; Fluttershy made a point of providing ample finger foods for her guests, so Dash had gotten into the habit of arriving hungry. She pulled herself up from the couch and strolled to the kitchen. There was a white box on the countertop, and opening it revealed a diverse selection of cookies. Dash took one, and when it proved to be delicious she allowed herself two more.
But now she needed to wet her whistle. Tea would have been nice, but milk would really hit the spot right now. Dash opened the fridge and found a sealed bottle front-and-center on the top shelf. She grabbed it, popped off the lid, and took a long gulp.
Just before the cold milk hit her tongue, Dash felt a pang of guilt; she tended to drink milk straight from the bottle in her own home, but it might not be the most courteous behavior in someone else’s.
But that guilt vanished when Dash tasted the milk. It was so perfectly smooth and flavorful and cold. It felt enriching going down her throat in a way that milk never had before… and despite its coldness, it caused warmth to blossom in Dash’s bosom. She found herself taking another gulp, then still more, unable to stop herself until she was licking the last drops from the rim.
Dash sighed with satisfaction. There was another sting of guilt; “help yourself” wasn't usually an invitation to deplete your host’s entire supply of milk. But it was so good, she couldn't possibly have stopped herself. She set the bottle in the sink, mentally preparing her apology for when Fluttershy returned from the shower.
When Rainbow Dash heard the shower turn off, she returned to the living room, and when Fluttershy exited the bathroom - with one towel on her head and another around her chest - Dash caught her eye.
“I hope I didn't take too long,” said Fluttershy. “Just give me a moment to get dressed and brush my hair, and I'll come right out. And help yourself to-”
“Yeah, about that,” said Dash, “I sorta already helped myself to some cookies, and like, all your milk. Sorry about that.”
“Oh, well the cookies were for you!” said Fluttershy cheerily. “And the-” she paused, her brow wrinkling in concern. “Milk?” she asked. “I don't have any milk.”
“Well, not anymore,” laughed Dash. “It just really hit the spot, so I just drained the whole bottle.”
“The whole…” Fluttershy was having a strangely difficult time parsing Dash’s words - and then realization flashed on her face. “Oh no!” she said. “Oh my goodness!”
Clutching the towel to her chest, Fluttershy rushed past Rainbow Dash and into her kitchen. She looked for the empty bottle - first in the fridge, then the countertop, and finally found it in the sink. “Oh nooo…” she whimpered softly.
“What's wrong?” asked Dash, walking up behind her. “Was it special or something? I can pay you back for it, if-”
“No, it's not that at all…” muttered Fluttershy. “It's, uh… oh dear…” she turned to look at Rainbow Dash, red-faced and looking down at the floor. “I, uh… oh, I can't say it…”
“Uh, Fluttershy?” said Dash, starting to feel genuinely worried. If there was something wrong with that milk, then you gotta tell me…”
“No, it's not… dangerous,” said Fluttershy, it’s just… that was my… breast milk…”
Dash felt her stomach jump as her brain and body processed this information. The thought of drinking her friend’s boob milk was just too weird… even if her tits were incredible. But the deed was done, Dash supposed, and her stomach settled… although her brain still needed some questions answered. “Why do you have a bottle of breast milk in your fridge?” she asked.
“I have a sort of… medical condition…” said Fluttershy. “My breasts get swollen with milk, and I have to pump them everyday or the swelling eventually becomes, uh… permanent…”
“That's why they're so big?” asked Dash.
Fluttershy shuffled her feet. “Yes,” she said. “Before I started pumping, my breasts would just swell up and grow and… eventually start leaking… I didn't know it was connected to the growth until I saw the doctor a few months back, and told her how my breasts hadn't stopped growing. Now I pump them every day, and… usually I just pour it down the drain, but I started thinking there might be some use for it… so I've been saving it for a little while.”
“Well geez, I'm sorry,” said Dash.
“No, I'm sorry,” said Fluttershy, “I shouldn't have left it where someone could find it.”
Dash sighed. “Look, I can tell this uncomfortable for you, Flutters. How about I just head home and we do this again later? I'm sorry, you're sorry, no harm done. Okay?” She opened her arms for a hug, and Fluttershy, still avoiding eye contact, returned the embrace.
The hug gave Dash another chance to feel the size and softness of Fluttershy's breasts - although it was a little weird now, thinking about how her breasts had produced the cold, creamy milk Dash had just gulped down. The two mares separated, and Fluttershy helped, grasping at her towel as it started to fall.
“Okay,” said Fluttershy, tucking the towel under her shoulders to keep it from dropping to the floor. “I'll see you later.”
“Hey, sexy,” said Rainbow Dash, posing inside the door frame. “It’s date night!”
“I thought you specifically said it wasn’t date night.” said Green Thunder. He’d be better put together if he’d been expecting his girlfriend to show up; right now, he was just wearing sweatpants and old t-shirt he’d pulled on as he ran to answer the door.
“Well, my hangout with Fluttershy got kinda cut short,” said Dash, stepping inside Green Thunder’s house.
“Oh yeah? What happened?”
“Uh, it was…” Rainbow Dash sighed, awkwardly running her fingers through her hair as she tried to find the words. “...kinda personal? But she’s okay, I’m okay, it’s nothing to worry about. And now my evening’s free! You’re not in the middle of anything, are you?”
“Do I look like I’m in the middle of anything?” laughed Green Thunder, indicating the sweatpants he was wearing.
“I dunno,” said Rainbow Dash. “Jerkin’ off, maybe?” She leaned down a bit, peering at his crotch. “Nah, you’re big enough that you wouldn’t be able to hide a boner in those pants.” Just to confirm her suspicions, she reached down and grasped his crotch, feeling the shape of his soft cock.
“Woah,” said Green Thunder. He was surprised, but he didn’t pull away. “You’re not usually this frisky in, like, minute one of date night.”
“What can I say?” said Dash, pulling her body closer to Green Thunder. “Sometimes a girl just needs it.” Now that she had her attention called to it, Dash realized that her horniness was a little strange; she’d just gotten through a decidedly bizarre encounter with Fluttershy, one where she’d inadvertently drunk milk that had been pumped from her friend’s boobs. That should have left her feeling weird all evening… but instead, she just felt a pleasant warmth in her chest and an insistent need in her crotch.
“Well, if my girl has needs, I’m not going to leave her out in the cold…” said Green Thunder, wrapping his arm around Dash. He reached a hand up to the crown of her head, grazing the back of one ear and then running his fingers through her long rainbow mane. “Why don’t the two of us…” He paused, shifting his body. “Hey Dash, are you, like, stuffing your bra?”
Rainbow Dash laughed incredulously and shoved Green Thunder away. “Whaaat? Dude, I’m not that insecure about my tiny boobs. What are you-” she looked down at herself, her face twisting in confusion as she lifted her hands to her chest. “What the hay…”
Rainbow Dash cupped her tits with both hands, feeling the unfamiliar sensation of squishy handfuls beneath her fingers. Dash’s A-cups had somehow grown. During the walk over to Green Thunder’s house, her boobs had swollen… just like Fluttershy’s…
Dash squeezed her tits experimentally and gasped, shuddering with pleasure. Her tits had never been this sensitive. They’d never been one tenth this sensitive. She kept at it, kneading her tits, moaning as waves of pleasure surged through her body, and she could swear they felt like they were getting even bigger.
“Dash, what’s going on?” asked Green Thunder, putting his hand on Dash’s shoulder.
“I don’t really know, Green,” said Rainbow Dash, “But, like… my boobs are growing, and it feels incredible. Oh Green, you gotta feel this. You gotta feel these tits, dude, they’re still growing and I wanna feel your hands touchin’ them…”
Green wasn’t sure he understood what was happening, but his girlfriend was begging him to feel her tits and there didn’t seem to be any reason to refuse. He reached out, and his hands took the place of Dash’s, grasping the soft handfuls through her shirt and gently squeezing them. Dash practically melted at his touch, leaning into him and sighing with pleasure. “So is this some kind of magic thing?” he asked, feeling her tits grow past C-cups.
“Oh, it’s fuckin’ magic, all right,” whispered Rainbow Dash. “It’s a milk miracle, baby…”
“Milk?” asked Green Thunder, raising an eyebrow - though his confusion didn’t stop him from groping Dash’s tits.
“Yeah, dude,” said Rainbow Dash. “You know how Fluttershy has giant boobs?”
Green Thunder coughed, his voice taking on an exaggerated chivalric tone. “I, uh, I’ve never noticed,” he said.
“Oh, shut up,” said Dash, giving him a playful punch in the arm. “So yeah, her tits are huge and we all know it. Well, get this: I drank a whole bottle of her boob milk and now I’m gettin’ big!”
“What?!”
“Yeah!” said Rainbow Dash. “Magic’s weird, right? I mean, obviously I’m gonna talk to Twilight or Zecora and make sure there's nothing to worry about… but I can’t do that just yet, Green Thunder. Do you wanna know why?”
“Uh, yeah?” Beneath his fingers, Dash’s breasts were becoming D-cups.
“Because it would be pretty awkward if I knocked on Twilight’s door and she saw me with my pants soaked through with pussy juice,” said Dash. “It would be rude of me to start humping her furniture after she invited me into her home. That's how horny I am, Greenie, and I need you to fix that for me.”
“Yeah, okay,” said Green Thunder. “You wanna hit the bedroom?”
“Sounds like a plan,” said Dash. She stepped back from Green Thunder, already missing the touch of his hands on her tits, and grabbed his wrist to drag him to the bedroom. Once there, she shoved him onto the bed and pointed a finger at his crotch. “Pants off,” she said, “I wanna see your long green cock, big guy.”
Green Thunder obliged. He'd already been tenting his sweatpants, leaving little to the imagination, but when Dash finally saw his hard, thick cock, her pussy pulsed with arousal and she could have sworn her breasts started to grow just a little bit faster. She pulled off her shirt, and her sky-blue breasts bounced freely, standing wonderfully firm despite their size.
“Geez, you're huge,” said Green Thunder, staring up at Rainbow Dash.
“I am fuckin’ big, aren't I?” said Dash. “What do girls do with tits this big?” She pressed the palms of her hands against the sides of her tits, squishing them together. “Hmm, I've got an idea… Greenie, sit on the side of the bed, all right?”
Green Thunder swung his legs over the side of the bed, and Dash knelt in front of him, placing her heavy, round tits in his lap. “Have you ever wished your awesome girlfriend had awesome tits so she could do this?”
Dash leaned her body forward, engulfing Green Thunder’s cock in her cleavage. “How's that feel?” she asked, moving her tits softly up and down on his dick.
“Feels good,” said Green.
“Fuck, me too,” said Rainbow Dash. “Something about having a long, thick, hot cock between my tits… feels really fuckin’ good. Mmmh, I'm still growing, I can't believe I'm still getting bigger…”
She moved her tits faster, squeezing them together, kneading the soft flesh with her fingers as her boobs surged past E-cups. “Green, I wanna make you cum, she groaned. “Are you gonna shoot a big sticky load onto my tits, baby? Gonna spill some hot white cum on my big blue boobs?”
“I'm… not too far off,” grunted Green Thunder, clutching the sheets as his cock throbbed harder, spilling precum into Dash’s cleavage. He reached up and brushed a strand of green hair from behind her ear, then ran his fingers down the shining strands of her lustrous rainbow mane.
“Good,” said Dash. “Oh geez, my tits are just swallowing up that big long cock… you're gonna disappear into my cleavage, big boy…” The head of Green Thunder’s dick, only barely poking out from between Dash’s tits, was spurting precum with each throb. The dripping fluid flowed down into Dash’s cleavage, making it slick and slippery as her bouncing, growing tits slid up and down the length of Green Thunder’s cock.
Finally, Dash’s tits grew large enough that Green Thunder’s cock was completely swallowed up, lost to Rainbow Dash’s sight. “Ohh, I’m even bigger than Fluttershy,” moaned Dash. “I used to be so jealous of her, and now I’ve got tits so big I can give a boobjob to every inch of your big long cock…” She bounced a couple more times, sliding the slick flesh up and down Green Thunder’s shaft. “This feels great,” she said, “But I really need to get fucked.”
She stood up, releasing Green Thunder’s cock, and pushed him flat onto the bed with a firm shove. She climbed on top of him, resting her big, heavy tits on his chest, and brought her head down for a kiss. With two giant tits between their bodies, it was a little harder than usual for their lips to meet… but when Green Thunder wrapped his arm around Dash and pulled her close, the squishy tits compressed down to a manageable size.
Dash’s kiss was ravenous, exploring Green Thunder’s mouth with a desperate passion. This was definitely the horniest Green had ever seen her; even after the endorphin rush of a Wonderbolts performance or the pent-up longing after a week spent apart, she was never quite like this. Her growing tits were turning her into a lustful beast, and all Green Thunder could do was try and keep up. Pulling her closer, he ran his hand through her rainbow hair, combing the thick mane with his fingers.
“All right,” gasped Dash, “I gotta get get fucked, Green. Just lie there and stay hard, all right?” She pulled herself up and knelt on top of him, groping blindly for his cock. “Damn, I can’t really see past my tits anymore,” she said, “But it’s so worth it. Feeling these babies bounce is gonna be awesome… and I bet you’ll have a good time watchin’ them, too…”
She gripped her cock and maneuvered it into her pussy, sighing with bliss as it entered her. “Oh fuck, that’s the stuff,” she groaned. “That’s my stallion’s big hard cock.” She met Green Thunder’s eyes and growled like a horny beast, flicking her head so that her long, dangling mane brushed across his face.
And then she was bouncing on his cock, slamming her hips down again and again with all of her trademark speed. Her tits were bouncing wildly, the momentum of her body making them bound up and down wildly. They were bigger than her head now, at a size that Green Thunder estimated as a J-cup… but it was hard to tell, given how fast they were bouncing. It was also hard to tell if they were still growing - every time they bounced, it looked like they were just a little bit bigger.
Green Thunder reached up and grabbed Dash’s tits, sinking his fingers deep into the marshmallow-soft flesh. Dash shuddered with pleasure as her sensitive boobs were touched, and she bounced faster, slamming her hips down onto Green Thunder’s cock again and again. He dug his fingers into her pillowy tits, groaning as his cock throbbed and his hips bucked. “Dash, I’m gonna cum…”
“Me too, babe,” grunted Rainbow Dash. “Fuck, my tits are so fuckin’ sensitive… I don’t know if I can even wear a shirt anymore… Just feelin’ a strong wind hit my boobs could probably make me cum… and your big hard cock is too fuckin’ good…”
Rainbow Dash cried out and slammed her body down onto Green Thunder’s throbbing cock, her pussy clenching just as Green shot his first spurt of cum. His dick pumped a thick load into her quivering body - maybe the biggest load of his life - but her climax lasted much longer than his. When he fell back, panting, she was still crying out - and when she finally came down from her orgasm, she fell forward, smacking him in the face with her colossal tits.
“So… I think they stopped growing,” Dash gasped. “How you doin’ down there, Greenie? My boobs aren’t suffocating you, are they?”
Green Thunder just mumbled - but there was a hint of distress in the muffled sound, so Dash rolled to the side, freeing him from under her tits. “Thanks,” gasped Green Thunder. “I mean, if I had to be suffocated by something, I’d definitely want it to be those boobs, but… thanks.”
“Yeah, these things are worth dying for, aren’t they?” said Dash, idly groping herself. “I don’t care what Twilight tells me, I’m keeping these.”