It was night-time in Ponyville, all was quiet and most of the residents of the town were asleep or on their way. Most of the houses were completely dark, or with only a few lights on from the few ponies still up. It was bedtime for pretty much everypony at this point, the Moon high in the sky, shining down upon the world as it slowly moved across the dazzling and starry sky.

 Ruby Pinch though, peeked out of her bedroom, giggling naughtily to herself at what she was planning to do. Her Aunt Cheerilee was passed out down the hallway in her and her mom's room. She had been drinking heavily with her sister and Ruby's mama, Berry Punch, before stumbling past Ruby's room to her own, and just like every other time that had happened, Ruby was gonna have some fun...

 The little filly quietly opened her door looked down the hall toward the living room. She could see her mom still on the couch drinking and eating snacks. Perfect. Ruby grinned as she slipped silently out of her room and into the hall, her tiny clit winking in anticipation of what she knew awaited her. Ruby walked softly in the opposite direction from her mama and quickly reached her aunt and mother's room. Pushing the door open as gently as she could so that it wouldn't creak, Ruby entered the adults' bedroom.

 Inside, lying under the the sheet and blanket, was a snoring Cheerilee, her body visible by both the light from the hallway and that of Luna's Moon coming through the blinds covering the window.

 Ruby giggled again as she crept over and climbed up onto the bed. Reaching out with her dark blue magic, she gently pulled the blanket and sheet off of her Aunt, letting them bunch up around her. Peeking over the mound of fabric, she gazed at what had brought her here, eyes bright with fascination.

 Between Cheerilee's legs was a large, limp cock, hanging flaccidly from its sheath. It was nearly as thick as one of the mare's legs, and the balls resting beneath it were as big as grapefruits. The genitals were a dark gray that looked almost black in the right light, and were slightly shiny with sweat.

 Ruby's Aunt Cheerilee had for some reason been born with colt parts instead of what was to be expected for a mare, and at first Ruby had not known what that had meant, as to be expected from a little filly like her.

 When she had innocently asked about it about two months ago, her Mom and Cheerilee had just blushed and giggled, telling her she wasn't old enough to understand. This had irked her, and one night, very much like this, she had snuck into their room after Cheerilee had gone to bed and Mama had stayed up. What she had found when she peeked under the blankets had surprised her, but had also made her feel...funny. It was a good kind of funny though, like her belly was full of butterflies, and after she had run back into her room, she had been filled with a burning curiousity for what was so special about her Auntie having boy parts...and why it made her fillyhood feel all warm and sticky to look or think about them...

 Ruby hadn't gotten the answer to those questions until a few weeks later. She had been bored and looking for something to read, and had found all sorts of magazines in her Mom's bedside drawer. They showed things like stallions putting their "things" inside mare's mouths, the mares' own "things", and even into their butts! She had even found a few that had mares that had parts like her Auntie doing it too. She had also learned about what they were called, "penises and cocks", "vaginas and pussies", and that what they were doing was called "sex". She had learned much more than that too, like what that nice feeling she got from being around her Aunt's cock was, and that had only increased her excitement and curiousity, the desires awakened within her now burning red-hot.

 Once she had absorbed all the information she could, she had put the magazines back and eagerly awaited her next chance to get at her Auntie's big and "sexy" penis, wanting to try out what she could.

 When Cheerilee had gotten home from teaching that day and taken a nap, little Ruby had seized her chance, soon finding herself learning first-hoof what fun and sticky things happened when she played with her Auntie's penis. Since then, she had taken every opportunity she'd gotten to do it again and again. When she couldn't, she stayed up to peek in on her Mom having sex with stallions, desperate to see and hear more and more about this newfound activity she had so lovingly embraced. Besides, she'd always thought her Mom was pretty, and it was nice to watch her have fun with the stallions, since she knew she wasn't big enough to do anything like that herself, and anything that made her mom happy was something she wanted to see.

 Back in the present, Ruby blushed as she took the flaccid shaft between her hooves and began to gently rub up and down its length, the warm and soft flesh pleasant on her fore-frogs.

 "C'mon Auntie...get hard for little Ruby..." she said quietly, smiling.

 After a minute of rubbing, the dick stood erect and throbbing, it being over a foot and a half/four and a half decimeters long now. Ruby smiled eagerly and laid down on her back, while pulling the dick down on top of her and began to gently lick at the slit of the cock as soon as it was in her face.

 "Mmm...it tastes just as good as ever Auntie.." the little filly said dreamily as she hugged the shaft closer to her and pushed her snout into the slit, the cock taking in her tiny muzzle easily as she took a moment to breathe in the concentrated musk.

 Up above her, Cheerilee's snoring rapidly turned into quiet moans as she shifted a bit in her sleep, soft "Mmm"-s and "Ahhh"-s drifting out of the older mare's mouth as her cock was toyed with.

 Ruby giggled happily and resumed licking at the slit with her tiny tongue, while eagerly stroking and grinding against the thick and veiny shaft that was still pressed to her body. She could feel every throb reverberate through her body.

 Predictably, all that attention caused slick and sticky globs of pre-cum to start oozing out, quickly coating Ruby's face and head as they emerged.

 After a couple more minutes of licking and slurping at her Aunt's cock, Ruby was already coated head to hoof in a sticky sheen of her Aunt's pre-cum and the little slut of a filly couldn't be happier. She loved this "game" so much, and could hardly wait for the best part of all...

 But, just as she went in for another lick, she heard something that made her freeze. She could hear the television turn off and the clank of a bottle.

 "What?! Mom's coming to bed already!" she thought to herself in a panic, looking rapidly from the cock in her forelegs to the door.

 She knew she had to hide quick, she just knew her Mom would be mad if she found out she was doing something so naughty. Looking around, the little filly didn't have any idea where to hide, at least nowhere that was close enough to reach in time.

 After a moment of more panic, her ears trained on the quickly approaching hoofsteps she heard coming down the hallway, she had an idea, her eyes going back to the throbbing pillar of flesh she was pressed against, and in particular the weeping slit at the top.

 "I can hide in Auntie's cock!" she whispered to herself, relieved. It was sure to work, if her Auntie's cock could fit her muzzle so easily, than it surely could fit the rest of her, especially with how slick she was.

 Wasting no time, Ruby pushed a hoof into her Aunt's slit and to her delight the wet and sticky slit opened up easily and her hoof began to slide down the shaft. Ruby quickly pushed the other hoof in and then shoved her whole body forward, practically diving down into the cock. Cheerilee's penis stretched around the little filly with not even a hint of trouble, taking in her head and torso smoothly, leaving only the lumpy bulge of her adorable body in the shaft.

 As her girthy cock swallowed up her niece, Cheerilee squirmed and moaned blissfully, her dreams filled with lusty images and thoughts of herself doing all sorts of things with her cock to the denizens of Ponyville.

 Ruby kicked her back legs and squirmed excitedly inside the tight shaft as she worked herself in deeper, her soft little belly and tight little butt being sucked and squeezed in while her head got closer and closer to where her Auntie's sheath was.

 "It smells so good in here...and its so warm.." she said quietly to herself, in awe of how nice this was.

 Ruby's rear hooves and tail slid into the slit with a quiet and wet slurp, like a trio of rose-colored noodles. Ruby then was quickly slid down the shaft and then squeezed backward through her Aunt's vas deferens tube, caused the loudest moan from the herm mare yet when she bumped into her prostate, before she passed into the epidydimis and then down into the right testicle. She fell into the cum filled sack with a light splash, her size causing the tightly spaced nut to bulge out. In response to the imbalance, the nut she wasn't in quickly began to fill and swell with a larger portion of the sack's churning cum until it looked even.

 Inside the hot testicle, Ruby was in heaven, surrounded by cum that was pooled up to her chest in the tight space. The hungry little filly immediately plunged her face into the pool and began to slurp up as much cum as she could until it was down to her bellybutton and her belly itself bulged out like she'd swallowed a cantaloupe.

 "Ahhhh...wow, I can't belive I'm in Auntie's balls!" she said with a happy giggle, all the times she had played with them and enjoyed what they produced, and now she was playing with them in a way she had never imagined she would.

 With a warm and satisfied belly full of cum, the little filly yawned and laid back.

 "I'll get out later..." she said quietly as she passed out in the half filled nut...