Sleeping With Sis

by Megapone

Rating: mature
Tags: Slice of Life
Length: 5893

Every night, Ruby Pinch sneaks over to her sister's bedroom and leaves her with a belly full of cum. When Berry Punch finds out what her daughter has been doing and forbids it, will Ruby be able to curb her dependence on Pina Colada's fillyhood?

When little Ruby Pinch first used her sleeping younger sister to have a little "fun," she told herself that it was a one-time thing. Now, each time Ruby sneaks over to her sister's bedroom, she leaves her with a squishy, bloated belly and a silent promise not to need to come back the next night.

When Berry Punch finds out what her daughter has been doing and forbids it, will Ruby find a way to curb her dependence on Pina Colada's fillyhood? Or will she continue to use her to get herself off, even right under her mother's nose?

A commission for TheOnlyOneWhoCared. Coverart by navanastra.

Contains: Foalcon, cum inflation, sleep molestation, hyper cock/balls, and futa. An expansion of a short from my clop drabble collection.

Published 1970-01-01 00:00:00 UTC
Last updated 2015-08-29 00:00:05 UTC

Sleeping With Sis

Ruby Pinch was sleepy. Her eyes were drooping closed, and every part of her body was aching and tired. But as much as she turned over in bed, she couldn’t sleep—she was too restless. Something kept her blood pumping, her thoughts spinning around till she felt dizzy. Somewhere in the back of her mind, she registered the heavy weight slowly hardening between her legs, but her conscious mind didn’t really register it. She peered over the side of the bunk bed and saw Pina Colada sleeping on the bed below.

“Psst,” Ruby  whispered. “You up?”

With a thump, she landed on the floor of the bedroom. Her eyes still drooping, she prodded Colada on the shoulder, whispering “Psst.” This time, Colada just yawned and turned away in her sleep.

The hard weight between her legs throbbed. Ruby yawned, then placed her forehooves on the side of the bed.

Pina snored cutely. She was sleeping above her blanket tonight, too warm to sleep beneath the covers. Her little foal muzzle was turned up in the air, and her eyelashes fluttered as she slowly and peacefully breathed out.

“Looks...comfy,” Ruby murmured to herself. Maybe...maybe Pina could help her sleep. She remembered them sleeping together when they were little foals. Maybe snuggling up with her could help tonight.

She grunted as she grabbed hold of the side of the bed and hoisted herself up. Her package slapped against the side of the mattress as she climbed up, a few drops of some kind of warm, milky liquid falling down to the ground.

Where her own mattress had felt lumpy and cold, Colada’s bed felt soft and warm. Ruby smiled to herself as she curled in next to her sister and wrapped her hoof around Colada’s tummy. At the same time, with a wet “schlip”, Ruby’s hardening stallionhood prodded up against the back of Colada’s fillyhood—and slipped inside.

Ruby had never thought much of her “special colt parts,” as Mommy had always called them. She’d played with them once or twice—the “penis,” as Daddy had called it, was fun to smack back and forth across her lap. She’d once asked Daddy why his penis was smaller than hers, and had never even gotten an answer, though he’d turned a funny shade of red when she’d asked. Still, she’d never really thought of her penis—or her balls, which each made a slight indentation in the mattress with their weight—as anything especially pleasurable.

That changed as soon as she entered Colada, as unwittingly as it may have been. Ruby gave a small gasp as the swollen head of her shaft pierced Pina Colada’s small mound, still dripping with precum all the while. Her balls swelled up at the first sign of a mate, preparing to fill Colada with Ruby’s seed.

Ruby grunted cutely, her hips thrusting upward purely on reflex—or perhaps sexual instinct.

Colada moaned quietly in her sleep, her already tight pussy closing around Ruby’s massive stallionhood as her womb filled up with pre. Ruby thrust again and again, her innocent filly mind justifying it as simply trying to find someplace comfortable to sleep. After all, there was a heavy, warm, almost unpleasant weight between her legs, and it was making it hard to stay comfortable.

Thrust. Thrust. Thrust. Some animalistic part of Ruby registered the oncoming orgasm, but the filly herself stayed ignorant. All she knew was that one moment, she was a little sweaty, biting her lip and squirming in her sister’s bed, and the next, she could feel a sensation of total relaxation and release spreading through her body as the package between her legs flexed and twitched.

Little Pina Colada barely noticed as her sister filled her up with cum. Her belly started to swell outward from all of the seed that Ruby was pumping into her, her distended stomach starting to rest on the sheets, heavy with all of the sloshing, warm cum inside. Some spilled back out through her fillyhood, covering the base of Ruby’s cock with her own seed. But still, Ruby kept cumming, fat globs of her seed splattering against Pina’s insides as her hips jerked softly.

Soon, Ruby’s distended balls back to a more manageable size, and her cock slowly softening once more. As the feeling of release slowly faded, to be replaced with a totally suffusing feeling of calm, she smiled in her sleep and wrapped one hoof tightly around her sister’s new squishy belly. Within seconds, she too was fast asleep.

She woke up a few hours later to the sunlight streaming in through the curtains. Pina was still asleep, so, very carefully, Ruby extracted herself from behind her sister and plopped down onto the floor. Her flaccid member had retreated into its sheath, and her mess from the last night had mostly dried up, so she was relatively clean when she walked into the kitchen.

“I’m hungry,” she told Mommy. Mommy, a purple-coated mare with a bright red mane and a bunch of grapes for a Cutie Mark, blinked owlishly down at her.

“Okay, sweetie,” Berry Punch said. She turned to a cabinet and started ruffling through boxes. “How about you get out a bowl and I’ll get so some cereal.”

By the time Ruby was halfway through her bowl of Bran Oats, a soft clopping of hooves echoed from the hallway. Pina Colada poked her head into the kitchen.

“Good morning, Pina,” Berry said. She plopped down by the table and lifted a cup of coffee to her muzzle. “How’d you sleep?”

Pina yawned and smiled drowsily. “Pretty good,” she mumbled. She stepped into the kitchen, her heavy, bloated belly smacking against the insides of her legs with every step.

Berry’s eyebrows went up. “Pina!” she scolded. “Did you have another midnight snack again?”

Pina blinked, then followed Mommy’s gaze down to her belly. “...Don’t think so,” she mumbled.

“Well, I’ll just have to check the pantry to make sure.” Berry Punch sighed. “Pina, I thought I told you to stop overeating like that. Although you might have been sleepwalking again.”

“Sorry, Mommy,” Pina said, looking down. “...I’m kinda hungry now, though.”

“Just sit next to your sister, then. I’ll get you something in a jiffy.”

As Berry busied herself with another bowl of cereal, Ruby gave Pina a little wave. The other filly waved back, then giggled when her full belly bounced a bit in her lap. Ruby smiled. Pina looked cute with that belly.

As the morning went on, Pina’s stomach slowly deflated, and finally returned to normal size sometime around lunchtime. But by then, its bloated image was left firmly planted in Ruby’s memory.

For the next week or so after that, nothing much happened. Ruby went about her day like any other filly without a stallionhood hanging between her legs, and Pina kept her normal-sized belly.

One night, though, Ruby found that, again, she couldn’t sleep. She closed her eyes and squirmed a bit deeper into her covers. It didn’t help. She felt almost suffocatingly warm.

Groaning in frustration, she kicked her blankets off. The motion set her stallionhood bouncing gently off of her tummy. She blinked up at it, watched it bob up and down. Just like the other night, it was long and hard; she poked at it and shuddered when a jolt of something went down her spine.

It wasn’t painful, though. It felt almost...good. So she touched it again. Ruby whimpered quietly when she felt her big, round balls plop out of her sheath and sag against her legs. They felt so heavy, so plump, so full.

She closed her eyes again, wishing she was asleep. But touching her “thing” felt really, really good. She bit her lip. Sleeping with Pina last time had felt really good, too. Maybe if she cuddled with her sister again, she’d be able to sleep.

This time, she didn’t even call out; she just plopped down to the floor, her member bobbing beneath her. Her shaft slapped against her belly as she climbed up to Pina’s bed. This time, though, it was easier for Ruby to get in position behind her sister.

A smile slipped across her face as she snuggled into Pina’s side. She slipped her hooves under her sister’s arm, hugged Pina tight to her chest. Just like last time, Ruby’s stiffening member slipped between Pina’s stubby, foal-smooth legs, poking against her fillyhood before slipping inside.

Pina let out a muffled groan; Ruby bit her lip, pressing her muzzle against her sister’s shoulder. This still felt good, but in a different way. Tighter. She felt her hips knock against Pina’s tiny rump, her shaft hilted fully inside her sister.

“Sshh,” Ruby murmured, her hooves drawing tiny circles on Pina’s side as her sleeping sister whimpered.

Her hips jerked softly against her sister’s. The bed creaked as Ruby snuggled further into Pina’s side, her shaft flaring up inside her soft fillyhood. Ruby bit her lip, squeezing Pina tight, as her orgasm hit. Her plump balls retracted against the underside of her leg-thick shaft as she unleashed her load inside of Pina’s tight, raw fillyhood.

Pina squirmed slightly in her sleep, then relaxed. Ruby relaxed too, sighing happily as a warm feeling spread through her body. That felt so much better. More and more of her seed flooded out from her overproductive balls, her stiff erection spreading Pina’s tight young fillyhood even wider as she pumped more and more of her hot cream into her.

Finally, her orgasm subsided. Ruby hugged Pina tighter and smiled to herself when she felt her hoof squish into her sister’s soft, cum-bloated belly. She could hear her seed sloshing inside; what felt like a full gallon of hot, thick jizz had bloated the little filly’s stomach out until her coat was stretched thin around it.

Ruby smiled. “Love you, Pina,” she mumbled sleepily. Then, still hilted inside her sister’s fillyhood, she slowly drifted off to sleep.

The next morning, she woke up to somepony shaking her. Ruby blinked, yawned, slowly coming to.

“...Mommy?” she mumbled, rubbing her eyes. “S’not...s’not a school day.” She blinked owlishly up at her mother. “Right?”

“Ruby,” her mother said. There was something strange in Berry’s eyes: something almost...angry. But that couldn’t be right. Mommy didn’t get angry. “You and Mommy need to talk.”

“Five more minutes.”

“No, Ruby.”

Slightly annoyed, Ruby let her mom sit her up. Her flaccid member, which had softened overnight, slid out of her sister’s fillyhood with a wet-sounding schlick. A few tablespoons of cum, which had been sealed inside overnight by the tight seal between Ruby’s medial ring and Pina’s labia, poured out onto the sheets. Berry sighed, worry lines on her forehead, and softly nudged Pina awake as well.

“Mommy?” Pina mumbled. “Good morning.”

Berry smiled tiredly. “Good morning, Pina,” she said. She seemed to be avoiding looking at the lower part of Pina’s body for some reason. “Why don’t you go take a bath to wake up? To...clean yourself off.”

“‘Kay,” Pina yawned, then plopped out of her bed. Her heavy, bloated belly slapped against the insides of her legs and she gave it a brief, disintered glance before turning back to the other two. “Can I use the bubble bath?”

“Yes, you may,” Berry Punch said. “The strawberry.”

Pina nodded, then yawned again. “‘Kay.” She set off for the bathroom, waddling awkwardly around her cum-bloated belly.

Berry turned back to Ruby. She was frowning. Ruby didn’t like that.

“Ruby,” Berry said, somewhat awkwardly. “You can’t sleep with your sister anymore.”

“But I couldn’t sleep,” Ruby protested, blinking herself awake. “I wanted to snuggle! Like with you!”

“You can’t snuggle with your sister in that way, Ruby. Or with me.” Berry grimaced, pointed at the space between Ruby’s legs. “Especially not with that.”

Ruby gaped. This was the first time her mother had ever separated her because of her “thing.” “Why not?” she demanded. “Pina helps me sleep! And it feels good—“

“I don’t care how good it feels!” Berry said. “It’s wrong, Ruby, and it’s not okay for you to do that to your sister!”

Ruby shrank back. The weight from her sheath on her thighs had never felt so heavy.

“I-I,” she stammered. “B-but Pina doesn’t mind.”

“Pina doesn’t know,” Berry said firmly. “And hopefully, she never will. We’re lucky you can’t get her pregnant yet, but…”

She trailed off. She noticed Ruby cowering and winced. She suddenly looked very tired.

“This has to stop, okay?” she said finally. “Just...no more sleeping with your sister. Do it again, and you know what happens?”

Ruby knew what Mommy was going to say. “Big trouble?” she asked quietly. Berry nodded.

“Promise me.”

“I-I—“ Ruby swallowed “—promise.”

A week later, Berry cleaned out the old storage room, disassembled the bunk beds, and moved Ruby into it. And for the most part, Ruby slept well.

Except for when she didn’t.

As time went on, Ruby found herself having trouble sleeping more and more often. One evening, for the fourth night in a row, Ruby found herself squirming beneath her pillow, her blankets having long since been thrown on the floor.

When she could take it no more, she sat up straight in bed, panting. Something throbbed at her crotch and she looked down.

Her shaft, fully hard and nearly as long as one of her hind legs, throbbed again. Ruby let one of her hooves rest on her full, throbbing sack and winced when she felt the hot liquid sloshing inside.

She felt so—so full. So heavy. So hot. She kept panting, stroking the side of her shaft ineffectually. It felt good, but it didn’t help the heat, or the fullness. If anything, it only made it worse.

Pina made it better. Ruby let out a soft whimper as she remembered the feel of her baby sister’s body against hers, remembered that warm tightness around her throbbing tool. She stroked it again, flinching as it throbbed particularly hard against her thigh.

Just this once, she told herself. Mommy didn’t even have to know. Just to be safe, though, she peeked outside of her door and made sure that the coast was clear before leaving her room. Ruby trotted carefully into the hall, making sure not to let the floorboards creak under her hooves. The walk over to Pina’s room seemed to take an eternity. Ruby’s erection slapped against her belly with every step, her balls slapping wetly against her legs and feeling fuller and plumper by the second.

All but whimpering with need, Ruby slunk into Pina’s room and quickly closed the door behind her. She eyed her slumbering sister with no small amount of thankfulness. Finally, she told herself, she’d be able to get some relief. Just this once. Pina probably wouldn’t even mind.

And even if she would, some part of her mind whispered, she didn’t even have to know.

Tears beaded at the corners of Ruby’s eyes as she lined her flare up at the space in between Pina’s legs. She didn’t know why it felt good, but she knew that if she put her “thing” inside Pina, she’d feel better. She stifled a moan, not wanting to wake Pina or Mommy, as she slowly slid herself inside her sister.

Pina groaned in her sleep, then mumbled something and turned onto her side. Completely hilted in her sister’s fillyhood, Ruby smoothed one hoof over Pina’s soft belly and slowly began to pump her hips back and forth.

This felt so good. Better, even, than what she’d felt before. Her heavy balls, each one more than half the size of her head by now, smacked against Pina’s flank as Ruby hilted herself inside of her. At first, she went gently, but then sped up, the pressure building, the heat swelling until it was nearly unbearable.

Biting down almost hard enough to draw blood, Ruby stifled a cry of pleasure as her orgasm burst inside of Pina’s womb. Almost too late, she remembered that Mommy couldn’t see Pina’s big, heavy belly, and so yanked her hips back. A few bursts of her fillycum managed to splatter the backs of Pina’s legs before Ruby managed to cover her erupting member with a blanket, moaning and squirming all the while.

When she was finished, she dragged the cum-soaked blanket back to her room and hid it in the back of her closet. As she tucked herself back in, her member having retreated back into its sheath, Ruby felt a small amount of guilt for using Pina like that.

But it was okay if she needed it to sleep, right? And she needed to. Ruby needed to do it to her. She would understand. And Mommy—Mommy didn’t understand. But that was okay. Ruby needed to feel good, and Pina would help her. Mommy didn’t need to know.

The first shards of understanding and guilt danced at the back of Ruby’s mind as, slowly, she drifted off to sleep. It was the first restful night she’d had in days.

And far from the last.

This went on for a while. At first, it was only once a week or so that Ruby would wake up, a throbbing stallionhood between her legs, and find release inside Pina’s soft rump. Before two months had passed, though, once a week became twice, then three times a week.

Most of the time, Ruby remembered not to make Pina’s belly big. One night, though, around five weeks after her first time, she forgot and left herself hilted inside Pina’s plump filly rear until the last of her orgasm had washed through her. As Ruby snuggled against her little sister’s big, bulging cum-bloated belly, a small note of panic stuck in her mind. It only grew as the night went on. She wound up sleepless in her own bed, staring up at the ceiling until next morning, as she wondered how Mommy might punish her for disobeying.

And then...nothing. Ruby went downstairs that morning to find Berry fast asleep on the couch, snoring loudly. The coffee table was covered with weird looking bottles, and her mother was steadily drooling onto the carpet. Pina came down about an hour later, still full of Ruby’s seed. Fortunately, Mommy wasn’t awake to see how her bloated belly sloshed and slapped against her legs; by the time she actually woke up that evening, Pina’s gut had deflated to a much less noticeable size.

As time went on, Ruby noticed a pattern: Mommy would always stay out late on Friday nights, and sleep really late the following day. As Ruby’s libido mounted, her need for Pina increasing to the point where she was “using” her sleeping sister every other night, Ruby learned to keep a regular Friday visit with little Pina. Bringing herself to orgasm felt good, but cooling down beside her sister, listening to Pina’s belly slosh with her love, felt even better.

Over time, Berry’s wariness went down, and Ruby learned to be sneakier about her visits, which were fast becoming nightly. Each night, whether she came inside or outside of her sister, whimpering with pleasure as she held her muzzle shut, Ruby would softly stroke Pina’s soft shoulders. She was powerless to keep her hooves from drifting down to her sister’s flank, which was rounding out and becoming plumper as she got older.

She thought of that flank every night, her stallionhood throbbing gently as she drifted to sleep, lost in the throes of her own afterglow.

Ruby Pinch couldn't concentrate.

Her left hind leg wiggled. Her snout twitched. Ruby just stared down at the page before her and glared.

She was supposed to be doing her homework. Unfortunately, her homework didn't seem to want to be done.

She squinted at the page, frowned. It all looked so boring! And kind of hard, too. She sighed, read the problem again—

—and just like her last four attempts, found her mind besieged by the burning, throbbing heat tingling at her crotch.

Ruby squeezed her eyes shut and groaned. She wanted to focus, She really did. But her stallionhood—she'd learned what to properly call it at a Sex Education class in school—had ideas of its own. It weighed heavily against her thigh, nearly as thick around as her leg. Her big, plump balls sat between her legs, forcing them apart. Her shaft throbbed against her leg again and she shuddered, an electric shock going up her spine.

She needed to concentrate—to do her work. But every time she tried to think about times tables, her member would throb again, and she'd lose track of where she'd been. Ruby's hoof drifted a few inches below her desk; soon, she was rubbing at the base of her meaty shaft, groaning softly as her need mounted higher.

Glancing out her window anxiously, she noted that Mommy hadn't come back from her shopping trip yet. Her heart beat a little faster. Maybe...

Her mind drifted again. Images of Pina: her small, round flank; her smooth coat; her wet, supple fillyhood... Ruby had to wipe away a bit of drool from the corner of her mouth.

But Pina was awake now. And if Ruby did...that with her, Pina might tell Mommy when she got back. If she'd been sleeping instead...

Ruby felt herself getting even harder at the thought. She bit her lip and glanced back down at her textbook. Her eyes caught on a note in the margins.

"Sleeping Spell," she read aloud, sounding out the words. "For in-som-ni-acs." Her chest got a little tighter, and her crotch got a little hotter. Her balls filling up at the thought of release, Ruby flipped to that page number and scanned the spell.

It...wasn't that difficult, actually. It looked like it was supposed to help ponies who couldn't sleep, but maybe it could make Pina fall asleep right now. Ruby glanced outside the window again. Nope. Mommy still wasn't home. Mommy usually stayed out till dark on Sundays. So maybe...

It was worth a try. She needed Pina right now: needed to be beside her, inside of her. She was sure she'd have understood.

She slipped off her stool. Her swollen balls slapped against the sides of her legs, her tool lurching with the sudden movement. A spurt of clear, milky liquid burst from the tip. It subsided into a stream as Ruby made her way downstairs, drooling its overfull volume over the steps as she made her way downstairs. Meanwhile, Ruby was carefully making sure to make as little noise as possible as she ran the spell over again and again in her head.

There was Pina—sitting with her back to her on the couch, reading a book. Ruby took a deep breath, summoned up her small reserve of magic, focused, and cast the spell. For a second, nothing happened. Then, slowly, Ruby watched her sister yawn, her eyelids fluttering, before slowly falling backward.

Ruby caught her with her foreleg. Once she was sure that her sister was completely asleep—she was snoring softly; kinda cutely, actually—she carefully lowered her to the arm of the couch.

Her shaft was throbbing madly now; Ruby bit her lip, trying to keep herself from just shoving herself into her sister right then and there. Her weighty stallionhood slapping against the bottom of her chest, she hopped up onto the couch and placed her hooves on Pina’s Cutie Marks. Her member was steadily drooling that whitish liquid now, and her balls felt so full and heavy. Ruby whimpered softly as another glob of pre bubbled from her tip, but reminded herself that she would feel better soon.

She pushed her flare against Pina’s rear. The smaller filly’s rump parted readily at her prodding. Then, her vision slightly obscured by lust, Ruby gently eased herself in.

She wasn’t prepared for how tight it felt. She closed her eye, chewing on the inside of her cheek as inch after inch of her meaty horsecock slipped inside of her little sister’s ass, lubricated by her copious amounts of precum.

It felt much different this time than all the others. It was slick, warm, and with a choking tightness that squeezed her tighter than she’d ever felt before. On the cushion, a dreaming Pina groaned softly and shifted her filly-sized hips around Ruby’s tool. Ruby inhaled deeply as she felt her member throb dangerously.

Peeking from one eye, Ruby realized that she wasn’t inside of Pina’s fillyhood at all—instead, she’d managed to insert herself into the other hole she’d occasionally noticed further up her butt. Maybe she should pull out and try the other one?

And then Pina clenched her rear around her length, and Ruby’s nostrils flared, her eyes widening. Oh, no. This felt way too good to stop. Snorting softly at the tightness, she eased herself in. Her fat medial ring, as wide around as her hoof, took a bit of work to get inside, but as soon as it slipped in fully, Ruby felt a warmth enveloping her whole body as she’d never felt before.

When her hips met Pina’s, Ruby almost came right there. As it was, her shaft seized up, throbbing and lurching madly as she hilted the last inch inside of her sister’s rump. Ruby took deep breaths, then blushed faintly when she saw a slight bulge near the middle of Pina’s belly. She drew her hips back a few inches and the bulge disappeared; she pushed back in, and there it was again.

Another glob of precum erupted from her tip, splattering against Pina’s slick insides. Ruby whined softly; she could wait no longer.

Gripping Pina’s flanks in her hooves, she slowly moved her hips back until around one-third of her shaft was left inside Pina’s rump; then, her stallionhood lurching, she shoved herself back in.

Meaty slaps echoed through the room as Ruby thrust again and again, plunging her pole deeper and deeper into Pina’s depths. Pina’s back shifted slightly on the couch cushions, but Ruby made sure to keep her straight. She lined her hips up with Pina’s, the first sensations of relief beginning to trickle through her veins. Groaning softly, she squeezed Pina’s flanks even tighter, her heavy, musky balls smacking loudly against her sister’s rear with each thrust.

As she felt her pleasure mount, Ruby moaned softly and curled her hooves around Pina’s waist. She bent over, her muzzle nearly nuzzling against her sister’s tummy, and plunged her shaft inside of her tight rear a final time.

The pressure at the base of her shaft reached a breaking point. With a quivering, aching cry, Ruby felt her member swelling up, bulging with her seed as her knee-length balls retracted toward her taint. Her hips jerked wildly as sweet, sweet release spread throughout her system.

Ruby rode her orgasm out like a wave, her slender hips slamming against Pina’s nice, tight rump again and again as her cum flooded into her sister’s belly. Fat globs of her cum splattered against Pina’s insides, ropes and ropes of spooge filling Pina up like Ruby had never filled before.

This orgasm was coming fast and hard. Ruby’s nostrils flared, her eyes rolling back as her cock lurched, clenched hard in Pina’s depths. What felt like more than a gallon of her hot seed rushed forth to fill Pina’s belly. Ruby could feel her sister’s stomach bloating beneath her hooves, growing tighter and rounder as it slowly swelled with the sheer volume of cum that her older sister was pumping into her.

On and on it went, with Ruby’s hooves slowly sinking into Pina’s cum-filled belly. As her orgasm finally reached an end, a tired Ruby felt the last breath of release fill her chest. She collapsed onto Pina’s bulging tummy, which by now made her look like she’d swallowed a basketball.

Her hooves gently massaged Pina’s bloated gut. Ruby could feel the bulge of her softening erection against her chest. She gave Pina’s belly a squeeze, and felt her aching balls force out another few cups of her seed into her sister’s rump in response. She snuggled into Pina’s big, warm belly, still rubbing it softly.

Pina moaned softly, her muzzle turning as Ruby’s weight set her jizz-filled tummy sloshing and churning. Ruby looked up at her and stared: a few dribbles of thick, creamy white had trailed out the side of Pina’s muzzle, streaking across her cheeks.

She leaned forward and sniffed. It had a hot, thick musk to it. She recognized that scent. It was the same smell that clung to her crotch just after an orgasm. But how had it gotten all the way up here?

She poked Pina’s muzzle open and saw more of her cum pooled on the other filly’s tongue. Ruby wondered what Pina was tasting right now. She’d never tasted her own cum before. She wondered…

Keeping Pina’s muzzle open with a hoof, Ruby stuck her tongue out and lapped at a bit of the cum inside of Pina’s mouth. It actually tasted good: warm, thick, and a bit salty. She tried to slurp up a bit more. As she went further into Pina’s mouth, her lips parted more and more, pressing forward until they finally met Pina’s.

And then Ruby was kissing her, her tongue working eagerly against Pina’s as she slurped up the last remnants of her seed in Pina’s mouth. Pina groaned softly into the kiss as Ruby’s tongue twisted gently against her own. Her hips jerking softly, and her member stiffening again at this new stimulation, Ruby delved deeper into the kiss, her hooves drawing small circles on the sides of Pina’s neck.

The familiar pressure mounted again soon enough. Ruby felt herself sinking another inch into Pina’s cum-bloated tummy as her tool stiffened inside of her. Soon, Ruby was panting softly, her lips still wandering across Pina’s cheek and neck.

Ruby gave a quiet, high whimper as she came again, her hips jerking as far forward as they could. Her second orgasm was nearly as big as her first. She kept her lips pressed against Pina’s, her tongue eagerly waiting for a new taste of her load as thick ropes of jizz burst from her tip to join the reservoir already in Pina’s belly.

On and on Pina’s belly grew, filling with more and more cum as Ruby’s balls released an impossible amount of seed. Ruby felt herself rising higher, Pina’s stomach swelling even taller and rounder beneath her; soon, her cum-filled belly was spilling over her thighs and folding over the sides of her chest. As her orgasm finished off, Ruby found that she’d been lifted so high by the volume of her own cum that she actually had to crane her neck downwards to meet Pina’s muzzle.

Little Pina moaned softly as Ruby finished filling her up, the bigger filly happily licking at any of the cum that was forced up from her little sister’s stomach. Then, as she finished, she tried—and failed—to wrap her hooves all the way around Pina’s stomach and laid her head down. A thin line of cum still trailed down the side of her muzzle.

She nuzzled her head into Pina’s cum-bloated belly. Laying her ear against Pina’s coat, Ruby could hear the lake of seed inside sloshing gently beneath her. Pina’s new belly was warm and soft, a comforting pillow against her chest. Feeling an overpowering drowsiness sliding over her alongside her afterglow, Ruby yawned, snuggled closer in with Pina, and slowly fell asleep.

A few hours later, a soft, high-pitched moan reached her ears. Ruby’s eyes opened blearily. She blinked a few times to clear the sleep out.

Below her, another moan rang out. Ruby glanced down, shifting her weight so that her softened stallionhood pulled out of its fleshy glove. It drooped off to the side, still covered in a thin sheen of her seed. A small river of her seed spilled out behind it, draining into a puddle on the couch.

Slowly, Pina’s eyes fluttered open. She yawned, then blinked toward her stomach. It towered above her like a hill above a valley. For a moment, neither filly moved.

Than Pina slowly raised a hoof, and poked her stomach. “My belly is really big,” she mumbled sleepily.

Ruby’s heart instantly started to pound in her chest. In a second, she was wide awake. Oh, no. She’d let Pina wake up, let her find out, and now she was going to tell Mommy and she was going to be in big trouble—

“Don’t tell Mommy,” Ruby said desperately. “Please?”

“Why not?” Pina blinked up at her with big, innocent eyes.

“Because…” Ruby looked down at the floor. “Because she told me not to,” she mumbled.

“Not to make it big?” Pina’s eyes grew wide. “Why not? It feels nice.”

Now that she hadn’t expected. “R-really?” Ruby stammered. She slid off of Pina’s belly and landed on the cushion beside her. Her stallionhood flopped over the top of her leg, her big balls drained for now. “Y-you mean that?”

“Yeah.” Pina screwed up her eyes and fell quiet for a moment. It took Ruby a second to realize that she was trying to sit up. Her belly, though it had deflated a bit from earlier, was still the size of a soccer ball. On a filly of her size, the effect was almost comical.

“Here,” Ruby said, her horn lighting up. Her telekinesis wasn’t the strongest, but she’d practiced enough that, with her help, the two of them were able to pull Pina into a sitting position. The smaller filly hiccuped as her belly flopped in her lap, its contents sloshing loudly. Then she poked at it with a hoof and giggled.

“I like it when my belly is big,” Pina said.

Ruby smiled hesitantly. “I like it too.”

“Can you make it big more? It feels good when you do.”

“You—you knew?”

Pina nodded. “Yup! Some nights you woke me up, but I stayed quiet ‘cuz I didn’t want to scare you away.” She tapped her chin thoughtfully. “And other times I woke up with a really big belly, too, only I didn’t know that it was you, but I guessed anyway. Mommy says I’m smart,” she added helpfully.

Ruby was still having trouble processing. So, she only offered a brief cough when Pina reached up and tapped her on the shoulder.

“I just had a dream about you doing something with your muzzle,” Pina said, blinking up at her. “What was it?”

“Um,” Ruby said, searching her mind. “It was...kissing, I think.”

“Kissing,” Pina said, sampling the word. “I think I liked it.”

“Kissing?”

“Yeah,” Pina said. “It felt good.” She smiled up at Ruby. “Can we do it again?”

“Y-yeah!” Ruby could scarcely believe it. She felt a grin edging its way onto her face. She leaned over Pina’s bloated belly and planted a gentle kiss on her muzzle.

Pina giggled. “That tasted good.” She massaged her big belly with both hooves. “Again?”

So Ruby kissed her again. As she pulled away, Pina sighed happily and smiled up at her.

“I love you, Ruby,” she said.

Ruby smiled, then curved a hoof around her little sister’s back. Her other, she brought around to rest on Pina’s belly. She rocked it back and forth on Pina’s gut, feeling its contents slosh back and forth. “I love you too, Pina.”