Caring for the Young One

by Mackstack

Rating: mature
Tags: Sweetie Belle, My Little Pony: Friendship is Magic, Alternate Universe, Other, Rarity, Slice of Life, Sex
Length: 10270

Sweetie Belle was born different from her other filly-friends. But now she is coming of age, Rarity realizes she is going to have to help her sister through some difficult discoveries about her body.

Sweetie Belle had a pretty easy childhood, never considering just why her body was different to the other fillies. Rarity had always understood her sister's unusual body, but dreaded the day she would have to sit her sister down and explain what it meant. But the young filly had to grow up eventually, and it seems that special time of life has arrived. With Sweetie Belle clearly in great distress, surely it was Rarity's duty as an older sister to help her sibling through these strange and troublesome times?

Contains: Futa, Foalcon, Cum Inflation, Impregnation,

Published 2016-10-29 00:00:01 UTC
Last updated 2016-10-29 00:00:01 UTC

I: Difficult Time of Life

I: Difficult Time of Life

Rarity’s face was a picture of concentration as she worked. Her tongue stuck out slightly and her brow was furrowed as she stitched together the last few seams of her latest project. After what had felt like days of work, she carefully dressed one of her mannequins in the new outfit. “VOILA!” She cried, her face a picture of joy. The perfect maid’s dress! She was ecstatic with pride. An outfit requested by Princess Celestia no less, for one of her personal members of staff! “Whichever pony gets to wear this would look rather dashing, even if I do say so myself…” Rarity chuckled to herself as she appreciated her work.

Her appreciation was interrupted by the sound of creaking and groans drifting down the stairs from the upper floor. Rarity – intrigued – trotted her way up the stairs and settled by the door through which the noises trickled. It was Sweetie Belle’s room, and as such Rarity was very cautious as she pushed the door open. She had no idea what to expect. But she certainly didn’t expect to see what she did. She was staring at Sweetie as she stood on her bed, one of her prized teddy bears wedged beneath her legs. A tear had been made in the bear's crotch, and Sweetie Belle was desperately plowing her cock into this makeshift vagina.

Rarity had never quite gotten to grips with her little sister being born futanari. She never knew how to act in regards to the genitals that hung between Sweetie’s legs - and her parents clearly never had been either - considering they had refused to give her the old ‘birds and bees’ chat. Watching her sister’s balls pendulum back and forth, smacking against the soft felt toy with a dull thud, she could do nothing but let out a short yelp in embarrassment. “Sweetie dear, wha-what in Equestria are you doing to Mr Bibble?!” Her young sister looked up from her strange mate, and stared longingly at her sister.

“Please Sis, you gotta help me get the funny feeling out of me! I can’t stop it and it’s so agonizing! I needed something to help me and Mr Bibble was all I could find!” She jumped from the bed, her cock covered in stuffing that stuck to the pre that smeared her shaft. As Sweetie galloped towards her, Rarity took a hurried step backwards out of the room, slamming the door shut as she went. Holding the door by the handle, she listened to the dull, heavy thuds as Sweetie rubbed her cock against the wood in desperation. Once the bangings subsided, Rarity braved a listen through the door. Pressing her ear to it, she could make out the sounds of the squeaking bed-springs as her sister resumed her urgent humping of that poor, poor bear.

A short while later Sweetie trudged down the flight of stairs. She peered left and right, scanning the rooms she passed as she searched for her sister. Finally, her eyes settled upon her, sat on one of the couches in the lounge. She had bundled herself up in a blanket, her entire body engulfed in the fabric. The little filly watched as her older sister lifted a short glass of whiskey to her lips. Several large ice cubes clinked against one another in the glass, betraying Rarity’s nervous shakes. Rarity’s ears pricked up as she heard her sister enter the room, spinning around with a start to confront her.

“Sweetie Belle! What in Equestria were you doing in there?!” She stared intensely at her sister as she shuffled awkwardly on her hooves. She clearly regretted coming to apologize.

“I’m sorry sis I just don’t know what came over me and I was really scared and I didn’t know what to do and my colt-bits felt funny and I had to scratch them on something and Mr Bibble was the only one I could find and…”

Rarity shushed her sister as the young filly's voice began to wobble and her eyes welled up. Rarity's anger quickly transformed into pity as she realized her sister was just confused and scared. As she would be at this age. She patted the space next to her on the sofa, encouraging Sweetie to come cuddle up with her. Still sniffling, she did so as Rarity lifted the blanket from around herself, carefully wrapping it around her sister’s shoulders.

“Okay Sweetie, I think it’s come to that point in your life where I need to explain a little more to you about your body. You see, you were born as a type of pony called a futa. These are very unique and special little ponies that have both colt-bits and filly-bits. Now, I understand it must seem strange, all of your filly-friends having different bodies from you. But you mustn’t worry, okay? You just need to understand yourself. Sometimes, dear, you’ll get funny feelings in your colt-bits, feelings like it needs to be touched. Is that what you were feeling?”

Sweetie looked down at her crotch and back up at her sister, nodding. “Do you mean in my cock and balls Rarity?” Rarity’s eyes widened with alarm at her sister’s lewd comments.

“Sweetie! Where did you manage to pick up such vulgar language?” Sweetie Belle’s eyes began to burrow into the floor. Obviously she’d said the wrong thing, she thought to herself.

“I heard the colts in Cheerilee’s sex ed class saying it. I didn’t know they were bad words…”

Rarity’s tone leveled out again, becoming reassuring once more. “That’s okay, dearie, but you mustn’t use words like that in public. Okay? You need to refer to those bits properly. Now, if you touch your… penis… enough, this special liquid comes out the end. That’s called cum, and it’s a very magical thing. If you put your penis into a mare’s vagina and get cum in there, she’ll get pregnant. Now, as fun as little bouncing baby foals are, they are a VERY big responsibility, alright? Not something a pony of your age should be burdened with. So I want you to promise me you won’t try and cum into any mares until you are older and ready for the responsibility, okay?”

She placed her hoof under Sweetie’s chin, lifting her head up to meet her sister’s eyeline. The young filly nodded assuredly, happy to have been given all the facts she so urgently needed.

“Good girl, sis. In that case, why don’t you pop along and play with your friends for a little while. You said you were going to go and meet up with the rest of the Crusaders today, didn’t you?” Rarity smiled awkwardly as her sister trotted from the room. As the door swung shut she turned back round to the coffee table, levitating her glass to her lips and taking a swig. “Sweet Celestia, that was a painful little chat.”

II: Dented Dignity

II: Dented Dignity

Night had arrived quickly for Rarity. She had been hard at work tailoring, stitching together intricate garbs and attire for the most affluent of clientele. Her craft captivated her, so much so that she had barely noticed the day slip past her. But looking up from her sewing machine, the world outside her window was dark. “Time to put Sweetie to bed,” she thought, “and then I can settle down by the fireside with a nice mug of hot cocoa and a good book.”

Pushing open her sibling’s door, she was surprised to see Sweetie was already long asleep. Her eyes were pinned tightly shut as tiny snores escaped her mouth. Pleasantly taken aback, Rarity backed out the room and slowly drew the door closed again. “Oh, bless. She must have been exhausted, playing out with her friends all day.” Rarity felt content and relaxed as she trotted away towards the lounge.

Sweetie’s left eye crept open as the dull clop of hooves on carpet became increasingly distant. She stared out into her empty bedroom, lit up slightly by the cool beams of moonlight that seeped in between her curtains. The filly lingered, stock still, only her open eye proving she wasn’t asleep. Waiting until the time was right, she peeled back her sheets and stared down at her genitals. She’d managed to go all day without mounting either of her friends, though she had convinced them both to try sucking on her testicles . They said they'd had fun, but none of them had gotten cutie marks for it...

It hadn't been overly long since her intimate moment with the teddy bear, but already she could sense her body needed another release. Punctuating these thoughts, Sweetie watched as her cock slowly and invitingly slid free of her sheath. As she leant forwards to watch, it crept towards her face before coming to rest mere millimeters from her muzzle. It hovered there, rising and falling slightly with each of her excited breaths. She couldn’t just sit there waiting anymore, teasing herself in the most painful of manner. She simply had to have it.

Inching further forth, she came to rest her lips against its flared head. She gave it a cautious peck of a kiss as she got a sense of the feeling, a sense of that incredible smell. It was something she couldn’t accurately describe. She could catch hints of so many different aromas in its overbearing musk, all of which beckoned her in. Pushing forwards, Sweetie felt her lips slowly part to accommodate the strange tool she’d always had but never understood. As it crept into her body she got a sense of every bump and groove that accented it, transfixed by its heavenly feeling.

But she didn’t want to take any more than she could handle. Not yet, anyway. She stopped her movement as her lips pressed playfully against her medial ring, marking a milestone in her first attempt at oral. Inquisitively she began to see-saw back and forth, working her cock with real care and appreciation. She was practically hypnotized by the weird beauty that inhabited her throat, and she could only oblige to worship it appropriately.

Her lustful – yet timid – beginnings had been left by the wayside as she began to slide up and down her own length at a faster and faster pace. She was enjoying this too much to go slow again. She could focus on nothing but the incredible sensations in both her throat and privates as she kept playing her depraved game.
But being new to the game, she didn’t quite realise how important it was to pace herself. She found herself caught off guard as the entire lower half of her body seemed to tense up in the strangest of ways. Sweetie’s face morphed into one of panic when she felt a torrent of liquid forcing it’s way up her urethra towards her awaiting mouth. She desperately tried to pull herself free, but – to her alarm – found she couldn’t open her jaw wide enough to release the flared head lodged in her mouth. So that mouth was the only place the flow could go. Her lips wedged open, Sweetie gagged and spluttered as the cum flowed thick and fast into her belly. She could hear the liquid sloshing back and forth most violently, weighing her stomach down like the aftermath of a heavy meal. Her skin stretched and grew to hold this vast mass inside her. Sweetie was terrified she would burst, but she couldn’t risk spilling any of her seed. If she made a mess and her sister caught her, the trouble would be immense.

Fortunately for Sweetie’s safety, the rush came to an end shortly after, the final few droplets dribbling from her shaft in a rather pathetic manner. From the sight of her belly, the little one looked like she could’ve been several months pregnant. Though this fact didn’t worry Sweetie at all as she slumped down, exhausted. She was asleep before her head had even hit the pillow. At least Rarity wouldn’t find out. That was all the mattered to her.

Ponyville awoke to the serenade of birdsong. The sun climbed into the sky as the moon retreated for yet another day, shining heartily down on the stirring population. Rarity had been up way before the dawn chorus, though. She’d been up since the early hours of the morning working on her outfits. Partially putting finishing touches to commissioned attire, but she’d also spent an unreal amount of time picking out clothes for her next visit to Manehattan. Sure, it was still a month away, but any excuse to look through her wardrobe.

The unicorn squinted out the window as the piercing sunlight caught her eyes. She put down the frocks she had been examining and wandered into the kitchen. Quick as a flash she had put together a simple breakfast for Sweetie Belle, and carefully loaded it onto a tray. She telepathically grabbed it as she walked towards the stairs. Who doesn’t love a surprise breakfast in bed?

Slowly casting Sweetie’s door open, Rarity’s eyes settled on the familiar shape of her sibling lying prone beneath the sheets. Even though none of the little filly was visible, Rarity knew her sister was under there. She could see the duvet rise and fall with each of her long, drawn out breaths. A mild clatter reverberated around the room as the unicorn rested the tray on Sweetie Belle’s bedside table. As she pulled the sheets aside she was hit by an oddly familiar smell. It was one she recognized, just not one that normally emanated from Sweetie Belle’s bed. No, this was a smell she knew from scandalous burlesque clubs in the city, namely the scent of a spent stallions ‘leavings’. This could only mean two things. Either a stallion had snuck into the house and had their vicious way with Sweetie, or...

Rarity flung back the sheets and found her answer. The mattress was stained top to bottom with semen. It had soaked deep into the sheets, leaving them dry and crusted in a vile manner. Judging by the position of the stain in relation to her sister, Rarity could piece together what had happened pretty easily. Sweetie Belle simply hadn’t noticed that as she swallowed down her spunk the night before it had swiftly proceeded to pour out of her rear, marking the bed with her shame.

Sweetie Belle woke with a start as she felt herself being dragged upright by her ear. She knew it was her sister. “Ow Rarity! what are you doing, I was trying to sleep! Let go, that hurts!”

With her sibling now fully awake, Rarity simply pointed at the hideous mess left in the filly’s wake. “Young lady, take your breakfast to the dining room and wait for me. I’m going to have to put your sheets through the wash and hang them out to dry. But when I’m done, we’re going to have a long, important chat.” Rarity stood with her hooves crossed, staring at her sister. Sweetie slumped from her bed in humiliation and crept by her sister, opting to leave the tray behind. She wasn’t really hungry yet.

The warm rays of sunlight poured in through the open dining room kitchen, bathing the room in a healthy, warm glow. Sweetie’s mood was far colder, however, as she idly pushed her cereal in a spiral around the bowl with her spoon. She simply stared out the window, watching her sister put out the washing. She was stood on her hind legs, throwing the washing over the line with her fore-hooves, before telepathically moving the pegs into place. Sweetie could feel her train of thought derailing as she watched. Her eyes slowly fixed on Rarity’s thighs, which swung left and right slightly with each of her movements. What sumptuous, lithe thighs they were… Sweetie could only imagine how good it would feel to squeeze that body, to run her hooves along her slight yet defined outline. Rarity seemed to wiggle her hips back and forth in the most teasing manner, swishing her tail, exposing her sex.

This unintentional show was all too much for Sweetie Belle, who suddenly felt a dull thud send sparks of pain through her body. She could feel that her now fully erect cock had smacked against the underside of the table, desperate as it was to become better acquainted her Rarity’s supple backside.

Leaning her fore-leg down under the table she grabbed her throbbing member and proceeded to jerk violently. Watching her sister was all the encouragement she needed as her mind flooded with the most perverse of thoughts. She wondered just how tight that little asshole of hers would be… Rarity was always talking about how she was saving herself for that perfect stallion. How it was her true desire to submit her body to her one true love on the night of their sublime white wedding. But how incredible would it be to take that dream from her, by force if necessary? All of her sisters plans of grandiosity and self-importance dashed as she found herself the eager, lustful breeder of a mare.

Not even a mare, but a filly.

A futanari filly.

Her own sister.

Sweetie tugged herself out of her lustful daydreams as she realized her orgasm was imminent. Unlike the night before, she couldn’t just drink it down, because now she knew that wouldn’t work. But at the same time, she wouldn’t be able to run to the bathroom, or even the kitchen sink. There wasn’t time. She crushed her urethra with her hoof in an effort to hold in the potent cum that forced its way up from her core, desperate to find somewhere for it to go.

There was only one thing for it. Leaning across the breakfast table she grabbed a large jug of milk that sat in place at its center. Fortunately Sweetie had poured some onto her cereal already, meaning the jug was only half full. She slung the jug under the table and pointed her shaft at the open top. Releasing her hoof, she cried out as the torrent broke forth. Having held it inside it had built up pressure, rushing free like a fire hose. As the spray collided with the surface of the milk, some of the jugs contents splashed out and onto the floor. As an urgent measure, she drove her cock down into the liquid in an effort to stop the splash-back. This seemed to work for her as she felt her now cold horsecock slowly empty its load into the jug. By the time she withdrew, it was entirely full again.

She practically threw the jug down against the table as her sister walked in from the garden. “Eat your cereal, Sweetie Belle.”
Sweetie looked down at her full bowl of breakfast cereal, whilst trying to stealthily cleanse her dick of the excess milk that remained on it.

“I’m sorry Rarity, I just don’t like it…”

“Oh, honestly darling, there’s nothing wrong with it. I guess I’ll just have to finish the box then.” Rarity grabbed one of the bowls from the kitchen, levitating it to her place at the table. She proceeded then to empty the contents of the cereal box into her bowl, before pouring herself a hearty slathering of milk.

“Now, there’s no need to beat about the bush. I know EXACTLY what you were doing last night, and I’m not happy about it. If you want to get a better understanding of your body then that is understandable, but that is NOT the way to go about it.”

Sweetie squirmed awkwardly in her seat, before dropping to the floor and slinking towards the doorway. “Where do you think you are going, Sweetie Belle? You are grounded after what you did. Grounded until tomorrow, ready for school.” The unicorn stared daggers at her little sister, making sure she began to climb the stairs to her room. After seeing her to her room and locking the door, Rarity made her way outside. She was going to go and seek some magical advice.

Twilight Sparkle was sat in her humble throne as Rarity spoke. The white unicorn was pacing back and forth, embarrassingly blurting through her sister’s situation. Twilight kicked her legs up onto the desk and rested a hoof against her cheek. It was obviously more than a little tricky for the alicorn to hide her boredom with her friends surely exaggerated story. She leant forwards as Rarity trailed off, her garbled words replaced by deep, gasping breaths for air.

“Okay Rarity, I understand the gravitas of this issue, but I don’t know quite what you want from me. I’m the Princess of Friendship. I’m not a biologist.”

Rarity rolled her eyes before directing them towards the Princess. She spoke with a rather patronizing tone. “I want you, Twilight Sparkle, to give me some advice on spells! I know that Celestia taught you everything she in the book! Plus you lived in a library before all of this castle malarkey, so you must have some body-mod spells under your belt!”

A single raised eyebrow was the only response Rarity got back before Twilight spoke up. “Of course I know ‘body-mod’ spells, as you call them. Why, when I was a filly I crafted my father a very special dragon cock. Two of them, in fact. Oh my, the things he could do to me and mother with them you would never believe. After I’d cast a spell to allow our bodies to handle them, of course…”

Rarity stared at the perverse creature before her, her jaw hanging open. She spoke through disgusted bile. “What is the matter with you, Twilight? That is disgusting, you freak!”

Twilight laughed as she stood from her throne and walked to her friend’s side. “Rarity, honestly now, I’m only messing with you! You should see the look on your face! So silly!” Her smile crept wider as she walked away again. She knew she wasn’t lying.

She rested her behind atop the table as she set the record straight. “Okay Rarity, here’s what I can tell you. There are spells that manipulate the libido, both to increase and decrease it. But these have all been crafted over years of study into the physique of stallions and mares. It would be far too much of a risk to try it on a filly. And while I could set to work on creating a new filly-centric spell, it would take months, perhaps even years of research. I’m sorry. All I can suggest to you is that if it gets any worse you take her to the hospital for a check-up. They’ll be better suited to dealing with the physical side of the scenario.”

Rarity's face was a picture of disappointment. She had wanted to steer clear of the doctors if she could. Being a unicorn she had always trusted magic over medicine. But nonetheless, if it was the only option... She quietly thanked her friend for the advice and turned to the vast double doors that marked the edge of the grand hall.

“Hey Rarity! If we get this sorted maybe the two of you can come out with me and father to celebrate!” Rarity held back a gag as she slammed the doors shut behind her.

"Animal."

III: Doctor's Orders

III: Doctor's Orders

“SWEETIE BELLE? I’M HOME!” Rarity’s sweet voice floated through the hallway as she stepped into the Boutique. No response. How odd. She quietly locked the door behind her and moved towards the stairs. “Sweetie?” Still nothing. Rarity stopped and checked the clock that sat in the living room. It was barely past lunch-time, so she couldn’t be asleep? What was she doing…

Oh no.

Grabbing the door-key from the table she dashed up the stairs as fast as her legs could move, and practically threw the key into the keyhole. As the lock opened with a satisfying clunk Rarity tore the door open. And she almost passed out from the sight that befell her.

Sweetie was stood on her bed, masturbating furiously. But her hooves weren’t resting on her cock. They were resting on the teddy bear that was skewered on her cock. The small hole torn into the nether region of the bear had been bust wide open. She’d been so aggressive with it, in fact, that the tip of her penis had burst free from the bear's neck, ripping the head off in the process. Stuffing lay strewn across the floor as Rarity spotted the decapitated head lying in a corner. But this was only the beginning.

Sweetie Belle was practically crying as she dragged the bear up and down her length, whilst simultaneously thrusting her hips against it. Her cock and balls had expanded to twice, perhaps even thrice their original size. Rarity was clueless as to how or why this had happened, but she was sure of it. The genitalia was now so big Rarity could practically see every red-raw inch of skin and pulsating vein from the doorway.

As the filly beat herself back and forth great waves of thick, string-like spunk were flung from her cock, splattering messily against the walls and ceiling. An especially large load shot through the air, colliding with a pristine family photo that sat on the windowsill. Rarity, frozen with shock, could only watch as it fell to the floor and shattered. With no signs of the onslaught stopping, Sweetie turned to look at her sister, the bear practically crumbling in her hooves as a result of the filly’s violence.

Through choked back tears, she cried out; “Please Rarity, my body feels weird, I don’t want to go to school tomorrow…” Rarity ran forwards and grabbed her sister. This was the time to go and get some medical advice.

Ponyville Hospital was a cold, uninviting place. The hallways reeked of bleach and cleaning products, and the nurses glided along with a cold authority. Rarity watched the elderly and the sick shuffle around her as she waited by her sister’s side. She had brought a frilly hankie with her to keep her safe from any of the foul diseases in this place, and she held it to her muzzle as the doctor arrived. Extending a hoof to the stallion, she quickly wiped it down with anti-bacterial lotion when he let it go. She refused to catch any of these unfashionable viruses.

“So, you must be Sweetie Belle.” Doctor Horse crouched down by the nervous filly’s side, giving her a warm, inviting smile. “We’ve heard so much about you. Only good things, don’t worry. You aren’t in trouble!” He affectionately tousled her hair as he stood up and invited the two into his office.

Walking through the doorway, Rarity watched as the Doc sat her sister down on an examination bed. Nurse Redheart also appeared in the room behind Rarity, slowly closing the frosted glass door.

“So, Ms. Rarity, the Nurse and I were having a look at your sister’s files, and I’d like to clear a couple of things up for the two of you. You see, futanari foals like you Sweetie Belle, all handle the heat season very differently. In the majority of cases though, the estrous build-up has no effect on the secondary pair of genitalia. But don’t for a moment think I am trying to scare monger. No, not at all. It is entirely common for foals to experience a similar bodily response to the one that you have. The build-up of hormones in the female body can influence the male genitalia dramatically. It may make you feel drowsy or increase your appetite, as well as potentially enhance the libido and size of sexual organs. Your case is rather unique, however, in the fact that both the size of your genitalia and libido have been greatly affected.”

He turned away from Sweetie, addressing her older sister directly. “Ms. Rarity, I am afraid we cannot tell you outright what is the best course of action. Each case is unique, and so we are going to have to complete a series of… ‘observations’ in order to comprehend the best course of action.” He chose his words very carefully; he knew how buzzwords like ‘test’ and ‘experiment’ tended to scare folks. “So would that be okay with you, Ms. Rarity?”

Rarity nodded assertively, and threw a glance towards her sister, commending her to do the same.

“And you, Ms. Sweetie Belle? Would you mind? We’ve just got a lovely tray of fresh toffee apples made up from the canteen. You can have the biggest one as a special treat when we’re all done. What do you say?”

Sweetie Belle also nodded, calmed by her sister’s confidence.

“Very good! In that case Ms. Rarity, I’m going to have to ask you to wait in the waiting room. If you stay here it could influence the results.”
Nurse Redheart held the door open as she ushered the unicorn out of the room. “I’ll just be outside Sweetie dear! I’ll catch you soon!” As the door swung shut she lifted the hankie to her nose once again, before taking a seat and throwing open a glossy gossip magazine, the front page proudly boasting:

INTERVIEW WITH THE ZEBRA FASHIONISTA THAT BLEW A HOLE IN HER CORRUPTED GOVERNMENT!

“Oh, those kooky zebras,” Rarity scoffed to herself.

Now they were alone, Doctor Horse sat at his desk, looking through a towering pile of notes and paperwork. “Okay Ms. Sweetie Belle, the first test we are going to have to do is a sensitivity test. We have to examine any changes in the biological structure of the male genitalia. Nurse Redheart, if you may, please.” The Nurse locked the door before moving towards the bed. She pulled over a stool before sitting in place by the end of the bed where Sweetie Belle was perched. The Nurse – without warning – pushed her hooves underneath the filly’s testicles, resting each in one of her hooves. Sweetie gasped. Her hooves were so cold. Redheart proceeded to lift each testicle slightly before lowering it back down. She watched as Sweetie twitched from side to side, the filly slowly biting her lip. The Doctor excitedly began taking notes of the young mares reactions, before abruptly holding his hoof in the air.

“Thank you Nurse Redheart, I think that’s enough for the moment. Now I need you to check for any cellular mutations in the flesh, and inform me of any changes in the aromatic outputs.” Now was the time for Sweetie Belle to start feeling nervous. She couldn’t speak doctor.
But she didn’t need to speak doctor to understand what the Nurse did next.

Redheart removed her hooves from under her testes, instead wrapping them around her shaft. As she began to stiffly pump the member up and down, she buried her muzzle deep into the folds of Sweetie’s scrotum. Further and further she pushed her head into the layers of skin, until she eventually came to rest. Sweetie’s eyes were wide as she felt an explorative tongue begin to caress every inch of her youthful skin. She couldn’t help but begin giggling as the Nurse’s breath tickled her ballsack as she swallowed back great gulps of her pungent scent. “Well, Nurse Redheart?”

“It’s very interesting, Sir,” her voice floated up, muffled through the flesh she was buried in. “The aroma is incredibly potent, you see. Far more so than that of any other foal her age, perhaps – dare I say – even more powerful than some of the stallions that we have examined in the past.” Her voice was a mixture of concern and intrigue as she continued to blindly caress the towering dick above her head. At least the Doctor assumed that tone was one of intrigue. It was hard to tell with all that meat drowning out her voice.

“Thank you Nurse, the research you are doing is exceedingly useful. You may remove yourself from the patient’s exterior.” With the instruction given Nurse Redheart pulled away, leaving a lingering trail of saliva connecting her tongue to the filly’s privates.

The doctor ticked off one of his notes, before rustling the papers as he searched for the next document he required. His search took a while, leaving Nurse Redheart hovering awkwardly mere inches from the filly’s genitals. It was taking quite a lot of effort from both parties not to jump back into the depraved procedure. Not that they knew of the other’s desperation, of course.

Doctor Horse eventually found the series of documents he needed, bringing them to pride of place at the front of the pile. Clearing his throat, he addressed the Nurse again.

“Alright then, Redheart. We’re about half way. The next examination requires an inspection into the effects of stimulation upon the flesh of the main body. I think you know what is needed of you.”

On his command she lifted her head up to the tip of the pony’s penis, licking her lips hungrily. She continued to play with Sweetie's shaft as she wrapped her lips around the engorged tip. Sweetie Belle was in agony. She’d been sat there, good as anything, letting this mare get on with what she had to do at her own pace. But this wasn’t a normal medical procedure. She was convinced of it. They’d come in, seen the mighty pleasure-tool she had at her disposal, and decided to play a series of tricks in order to get their hooves on it. Well, Sweetie wasn’t having it. If these ‘tests’ were going to go ahead then so be it, but by goodness they were going to be on Sweetie’s terms. Her dirty, depraved terms. As the Nurse experimentally ran her tongue around the outer rim of Sweetie’s flared head, she felt herself being grabbed by the cheeks. Looking up, her eyes met those of the young filly that stared down at her.

“I’m sorry, Ms. Redheart, if you think I’m going to let you use my body any more, you’ve got another thing coming. I want you to remember something. I’M IN CHARGE NOW. You do what I say, when I say it. Unless you want me to run out that door and tell my sister exactly what kind of things you tried to do to me.”

Redheart found her whole body frozen, her mind filled with the strangest desires of subservience. What was it about this situation that mesmerized her so?

Was it that impressive cock that twitched teasingly against her lips?

Was it the way the filly had grabbed her, taking control of the situation like the sexual dominant she was quickly becoming?

Or was it the fact that she had seen that, from the corner of her eye, the Doctor had ceased taking notes and begun to feverishly masturbate, dropping all pretense of these experiments being scientific?

He liked to watch his Nurse fuck her patients, and he knew this incredible filly would blast her into next week. “Do what she says,” he gasped through baited breaths, “I want to see her dominate you.” And so the Nurse looked back to the filly she who’s cock she was speared on, awaiting direction. The balance of power had shifted.

“Okay then, Nursey. If you want to check how stimulated I am, then go right ahead. You know my cum is nicely pent up in that shaft, so I want you to draw it out.” Redheart responded. Dragging her tongue back from the filly’s rim, she began to slobber around the slit of her head. Running her tongue suggestively around it’s edges, she watched as the filly’s head lolled back and her legs wrapped around the nurse’s shoulders. Pushing forwards, she positioned her tongue against the entrance to the filly’s urethra, before forcing the skin apart. It was incredibly tight, obviously having never been penetrated or played with before. The Nurse smiled wryly as she drove her tongue inside with as much effort as she could physically muster. Sweetie screamed with joy as she felt the walls of her cock part around the Nurse’s slick, wet tongue.

Rarity looked up from her magazine. “Honestly darling, it’s just a medical check-up. Don’t be such a baby.” As the screams subsided, she returned to an especially interesting article about Mayor Mare’s plans to build a wall around Ponyville, inspired by Dictator Trixie’s dome idea.

The whole of Sweetie Belle’s body shook as the Nurse crept further and further down into her urethra. Her whole cock felt like it would split in two if this whore wedged herself any deeper inside. Finally to Sweetie’s infinite relief, the shameless mare ran out tongue. She’d managed to force her entire writhing organ into Sweetie Belle's vast futa cock, and the filly could see how happy Redheart was with herself for managing it.

With the filly’s urethra now held wide open, it was impossible for Redheart to stop the rush of spunk that assaulted her mouth and throat. This was her favorite part of the job, watching her patients twitch and writhe as she guzzled back their seed, making them fall in love with her body. Holding the load in her mouth, she pushed it around with her tongue, savoring that sweet taste. Gulping it down in a single motion, she pulled herself free, smiled, and licked her lips. She rose to her hooves, and planted a wet, sloppy kiss on Sweetie’s forehead.
“Good girl Sweetie Belle, we’re all done here! You can trot along to your sister now!”

Sweetie cocked her head as she looked at the Nurse, gazing down at her.

“Excuse me?” Sweetie Belle’s voice was filled with shock at her naivety. “I don’t remember putting you in charge. What, you think you can just drink my pre-cum and waltz away? Ha. This is my game now, and you’re going to do three very simple things for me. First, remember I’m the boss. Second, turn around and show me that cute behind of yours. Third, pull that pussy apart for me.”

Wait, that was just pre? Redheart gulped. Begrudgingly she accepted the turn of events as she felt her entire body being spun around, guided by the filly’s hoof. Finally she came to rest staring at the far wall, with the folds of her vagina being playfully prodded by Sweetie’s awaiting cock. The voice of the Doctor drifted over. His reassuring tones had been replaced by ones of pure aggression and forcefulness.

“By Celestia’s name Redheart, you’d better get on with it or else I’m going to come over and bust a nut inside you myself. And so help me I won’t be gentle. You don’t deserve it.”

Spurred on by the Doctor’s harsh yet erotic words, she lowered her behind down onto the shaft below her, moaning as she felt her soft lips parted by Sweetie Belle’s spear. The Nurse had no time to get used to the hunk of flesh lodged inside her as her entire body was dragged down by the filly’s hooves. She had surprising strength. Either that, or the Nurse’s body had gone weak with lust. Either way, she put up little resistance as Sweetie Belle began to use and abuse her back end. Slamming her down against her crotch before throwing her back up into the air again, Sweetie eventually let go of the mare’s behind. She trusted the breeder-mare knew what to do at this point.

Sweetie began to cruelly mock the Nurse, her clouded brain crushing her normal personality. “Do you enjoy breeding with foals? Does it make you wet, knowing that any moment now you’ll be filled with the children of a pony so many years younger than you? Ha, I don’t even need to ask, of course it does. Just look at the state of your pathetic back end. I can feel your juices streaming down my cock.”

Redheart had never been so content in all her days as a nurse. She’d dominated so many of her patients, and while they’d all loved it, she’d grown tired. Without even realizing it she had longed to be put in her place by somepony, anypony. And now she was. And it felt great.
What made the Nurse feel even better was the fact that she saw Doctor Horse rising from his chair. He’d grabbed one of the rich, dripping toffee apples in one hoof and sauntered over towards his assistant. Her eyes darted from his face down to his immense twitching horsecock that swung from side to side as he walked. Normally hidden from view of patients in its sheath, once it was exposed it was a hell of a sight to see.

Having access to all of the medical creams and drugs in the hospital, Doctor Horse had gone mad with power years ago. Every day, Redheart would catch him rubbing some paste into his shaft or injecting his balls with a syringe full of some strange concoction. All this in an effort to give himself the mightiest cock of any pony in the hospital, to put the stallions Redheart bred with to shame. And while it had worked, it had worked perhaps too well.

His cock was vile. It was the length of his entire body at full mast, daubed with veins so fat they could’ve been mistaken for sausages. The medial ring that marked the middle of his shaft was so wide that Redheart had felt convinced the first time she rode it that it would tear her in half. Fortunately she had tamed it, of course. His nutsack - whilst not overly impressive in size – was freakishly heavy, filling with seed so quickly that no sooner had he orgasmed he needed to do it again. And boy, how impressive that seed was. Redheart didn’t know what combination of drugs had managed it (nor did she want to) but somehow the Doctor’s potency was so intense that he could impregnate almost anyone - or anything - he tried to. She still shuddered at the memories of the time he fathered a litter of pups.

But at this precise moment, she cared about none of those worries. She was about to be double-teamed by the virile Doctor and this incredible filly, and she was gagging for it. She opened her mouth as wide as she could and closed her eyes tight in anticipation as the Doctor placed his fore-hooves up onto the hospital bed.

Oh, yes! Redheart’s mind was awash with lust as she felt the vast, rounded mass of his head being forced into her mouth. It felt so good, and it was so wet with his sticky pre-cum! But wait a minute, this pre-cum tasted really strange...

Peeling her eyes opened, she saw the Doctor’s back leg disappear past her head as her climbed over her. Wedged between her lips was the toffee apple, leaving the Nurse looking akin to a hideous stuffed pig. Doctor Horse moved along the hospital bed before coming to rest in front of Sweetie Belle. Still bucking away furiously at the mare, she looked up at the doctor and licked her lips invitingly. “So, you want a little piece of the action too, big boy?”

Doctor Horse couldn’t help but snicker at the filly’s ridiculous over-confidence. He pushed her down onto her back with a hoof, ignoring his assistant’s pleasurable moans as she was pivoted backwards with the motion. “Listen here, young filly. You might think you’re a big shot just because you’ve broken your way into the easiest mare in the building – other than your sister, of course. But you’re not. This is my hospital, and I am in charge. You aren’t some dominatrix mare. You’re just a filly in her mother’s high heels that needs a good, stiff cock inside her. And so until you bring my day to a satisfying climax, I guess I’m just going to have to shut you up for good.”

With that he rammed his cock forwards into Sweetie Belle’s cute little mouth, parting her lips under the weight and pressure of his freakish member. On the verge of orgasm already, he gave it no time or second thought as he manipulated his way into the filly’s tiny body, until he finally felt her lips come to rest against his medial ring. There was no way in Equestria she’d be able to fit THAT inside her. Not without some major surgery, anyway. But that was just as well, because as the Doctor looked down at the filly’s body he saw her belly distended so incredibly around his own cock he was surprised she hadn’t passed out.

“Very impressive, little one. Most ponies end up overwhelmed way before this point. I would press forwards, but I don’t think that mouth of yours would allow it. So, we’ll just have to make do!” Doctor Horse cried out in excitement as he drew his cock back from the filly’s belly, up and throat and into her mouth. Refusing to quite pull himself free, he lingered there for a few seconds, before ramming it home again as quickly as he could. He listened as both the mares groaned in euphoria before Sweetie was cut short by the doctor’s ballsack smacking her in the chin. The two thrusted as quickly as they possibly could, Sweetie Belle trying desperately to keep up with the power-hungry maniac in her esophagus. Nurse Redheart had lost all signs of civility, now just thrashing wildly up and down on the foal’s crotch, smacking up and down with such ferocity, the entire bed shook.

As the spit-roast raged on, Sweetie was the first to cum. She moaned through the slab of meat inside her as her whole body began to convulse. The hardest orgasm of her life, she could feel herself becoming light headed as she launched load after load into the Nurse’s cavernous pussy, seeping down into her very womb. Redheart could feel her belly gravitating floor-wards with each mighty load dumped inside her, and she’d never felt better. She screamed for more, clamping down on Sweetie’s cock in an effort to milk her of every drop she could muster. As the final wave came to an end, Redheart could feel the semen pushing it’s way up her throat. Having filled every inch of her body, it had nowhere else to go. She felt it butt up against the apple lodged in her mouth, before eventually pushing its way past. The apple bounced down onto the floor as the cascade of seed hurled itself out of her mouth.

Doctor Horse craned his head around to see the carnage that laid in Sweetie’s wake. The sight of his assistant’s pregnant belly, swinging back and forth in the most incredible manner was enough to send him overboard too. He dropped to his knees as he felt his own cock give way to the torrent of semen within, firing red-hot seed into the belly of the mare below him. Once the ordeal was over, he pulled himself free and jumped down onto the floor, wobbling slightly on the landing. He inspected the belly of both the filly he had plundered, and his assistant. To his horror, Redheart’s belly was vastly bigger than Sweetie Belle’s. Her load had dwarfed his. How humiliating for him.

Rarity looked up as she heard the office door creak open. Finally. She’d gotten through about seven of the magazines in the waiting room, she couldn’t of waited much longer. Out tottered a red-faced Doctor and an incredibly happy looking Sweetie Belle, who heartily devoured a toffee apple. A toffee apple stained white. Weird. Doctor Horse mustered up the courage to speak.

“Hey Ms. Rarity, I’ll, uh, make this quick for you. After completing some rather, um, thorough tests… we’ve settled that this is the most extreme case we’ve ever seen. There’s very little in our repertoire that could be of help, so we can only suggest you try something a little controversial.” The Doctor revealed a large, vulgar butt-plug from behind him. Where was he keeping that? “Okay Ms. Rarity, this is a butt-plug. A special, vibrating butt-plug. What you need to do is this: every night before Sweetie Belle goes to bed, insert this into the rectum and switch it on. Come the morning, switch it off and remove it. Rinse and repeat until the lustful feelings subside.” Rarity looked skeptical.

“Are you sure? That sounds like quack science to me…”

“No no no! This is a new scientific breakthrough, just off the grapevine! I implore you to at least trial it. You do want her to get better, right?”

Rarity shrugged her shoulders. She had come for advice, after all. Taking the plug, she thanked the doctor and headed for the door with a smug Sweetie Belle in tow. Once they were out of the building, Doctor Horse began to rub his hooves together, laughing to himself. “That will show that self-satisfied filly not to try to compare herself to me and my incredible cock!” Looking around, Doctor Horse realized several patients were staring at him, confused. Awkwardly he stopped laughing to himself, throwing his hooves down to his side. “Er, next please.”

IV: Desperate Times & Desperate Measures

IV: Desperate Times & Desperate Measures

Sweetie Belle sat on the edge of her bed, her arms crossed over her chest. She shook her head defiantly as her sister approached, wielding the vibrating plug like a weapon. The hunk of silicone looked unwieldy and terrifying, and that was before Rarity had even hit the power switch on its underside.

Rarity stopped her approach, her head sinking in resignation. “Look, Sweetie, I know how uncomfortable you feel about this, but it’s what the Doctor recommended. And we have to listen to our doctors, don’t we dear?” In response Sweetie dramatically threw her head to one side, holding it high in defiance. “I’m not budging Rarity! I don’t want that thing anywhere near my behind! Things come out of there, they aren’t supposed to go back in!”

Rarity couldn’t help but smile at her sister’s naivety. Oh, how little she knew about the world. She sat down by her sister’s side, resting a reassuring hoof on her knee. “Come along, Sweetie dearest, you’re worrying over nothing. I know it seems wrong, but you’ll get used to it after not too long, won’t you? And then it’ll become just another part of our nightly routine, yeah? Clean our teeth, get into bed, pop in the butt plug, go to sleep!” Rarity moved around, so she was staring her sister in the face. She smiled calmly, never breaking eye contact with the concerned filly. “If you won’t do it for the doctor, will you please do it for your sister? Hey, if you do, I’ll take you to Manehattan this weekend! And then the next, and then the next! In fact, if you promise to try this plug until the doc recommends you stop, I’ll take you to the city with me every week! What do you say?”

She stared nervously as she waited for an answer. If Sweetie didn’t agree on these terms Rarity was in real trouble. The Manehattan trips were her trump card. Sweetie slowly uncrossed her arms as she thought, before coming to rest by her side on the bed. “Okay sis, I’ll do it. For you. But you'll have to put it in for me. I’m not really comfortable with it.”

Rarity didn’t have any choice. If she didn’t do it, Sweetie sure as heck wouldn’t. And so, reluctantly, Rarity pushed her sister’s legs apart and moved towards her rear. Telepathically holding the plug by her side, she hovered forwards, until it rested teasingly against Sweetie’s plump butthole. It was at that moment Rarity hurriedly withdrew it again. Looking around, she realized she had nothing to use for lubricant. She couldn’t just force it in dry, she didn’t want to hurt her poor sister in a period of such difficulty.

So the only option was to wrap her tongue around its tip. She slathered it with lubricating spittle as she dragged her tongue across the entirety of its flared body. She watched as her sister bit her lip and shuffled left and right, her cock slowly making itself visible from her sheath. It turned her on knowing her little sister was enjoying the show, getting all hot and bothered as she watched her older sister sucking on the butt plug that was about to be forced inside her.

Having decided the ‘medical apparatus’ was now appropriately lubricated, she started to push it against her sister’s back passage once more. Slowly but surely she pushed it into her body, watching her sister’s expression of euphoria as it crept inside, inch by inch. She made sure to move slowly as she could only imagine how difficult the ever-expanding flare must be to take. Finally Sweetie let out a guttural moan as they plug jolted forwards, the filly’s gaping anus drawing shut, swallowing it into her body. Rarity leant over and slowly pushed her sister down onto her side.

“Now Sweetie, I want you to close your eyes and go to sleep. Why don’t you try counting dresses for me? Rest well, my sweet.”

As the little filly closed her eyes, Rarity watched as her cock slowly subsided back into her body again. Once it was fully enclosed by her sheath, then she proceeded to tuck her sister in. Having finished with the final corner of the duvet, she leant in and planted a long, affectionate kiss on Sweetie Belle’s forehead. As she lingered, her horn bathed the room in light as her magic connected with the switch adorning the vibrator. Clicking it on, she watched as her sister’s body began to shake slightly with the reverberations from below, clearly in mild distress. Rarity closed her eyes and walked away, telling herself to ignore it. “Get it together, Rarity. Doctor’s advice is doctor’s advice. Don’t question it, and see her in the morning.”

Sweetie Belle stared at the ceiling in agony. Every inch of her body ached with red-hot lust, as the infernal plug lodged in her rectum shook with an ever-increasing ferocity. Despite masturbating and orgasming three times during the night so far, she couldn’t beat back the flood of desire that engulfed her.

She settled that there was only one course of action. Climbing to her hooves, she stepped awkwardly through the multitude of wet patches on her bed and floor, trying her best not to slip and land face first in her mess. As she cleared the puddles and reached her door, she looked back to see a trail of white, sticky footprints following her movements. How gross. But no matter, she could clean tomorrow.

She quickly trotted down the corridor towards her sister’s room, trying desperately to ignore the urgent cries from her needy body. “Calm it down, Sweetie. Just get down the hall and Rarity will have no choice but to help.”

Arriving at her sisters door, she pushed at it experimentally. Fortunately, it was unlocked and off the latch, so it yawned open with ease. And there was her prize. Her sweet, sweet release.

Rarity laid on her back, only her head and left hoof visible above the sheets. Her eyes were covered by her sweet frilly eye-mask, while the rest of her body was enveloped by her duvet, wrapped like a perverse present for good little fillies. Sweetie hoisted herself up onto the bed and found herself stood over her sister. She looked intently at her sister’s face, wondering just how good she would feel. She had been simply gagging to feel a mare again after her appointment with Doctor Horse and Nurse Redheart, and her sister’s pretty mouth would be the greatest possible choice for her.

There was no time to wait. Sweetie flung herself forwards, busting Rarity’s lips apart with a cruel speed. Rarity woke with a start as she felt a sensation like being hit by a train. Snapping the mask urgently from her face, she looked up to see her sister plowing her cock deep into her throat. She cried out for her to stop, but nothing beyond a muffled moan escaped her meat-filled mouth. Rarity began to conjure up a spell to move her away, but suddenly she was captivated by her sister’s facial expression. Tears of joy were rolling down her cheeks as her face shone with an incredible smile. Rarity hadn’t seen her sister this happy since all of this trouble began. Despite Rarity finding this whole engagement strange and embarrassing at first – she had to admit – she felt far happier knowing it was helping her sister feel so much better. Deciding to accept her sister’s intense thrusts, she seductively moved her hooves up Sweetie’s thighs, coming to rest at her midriff. She motioned back and forth, encouraging Sweetie to speed up.

And of course, Sweetie was only happy to oblige. Her movements suddenly became sporadic and jerking as she shifted her weight forwards and practically fell onto Rarity’s head. She wrapped one hoof around the back of her neck and the other around her horn. With her head held stock still, Rarity was her sister’s sexual plaything. She had all but submitted to her as Sweetie began to ram against her face again. But now she moved with an incredible speed and force, pulverizing Rarity’s muzzle against her crotch. Rarity could feel tears of effort begin to creep from her eyes as the blowjob turned into an intense face fuck. She could do nothing but brace her hooves against the headboard as Sweetie battered her face this way and that. Rarity almost couldn’t handle it, but she also just couldn’t believe just how much she adored the sexual aggression of her sister.

The initial wave of cum that launched from Sweetie’s body was unexpected. Sweetie had barely realized it was coming before it rushed free from her cock. Pouring forth into her sister’s open mouth it sloshed around her belly before settling, only to be joined by yet more spunk as it cascaded down her esophagus. Rarity could feel every inch of flesh around her mid stretch and deform in order to hold her heavy midnight snack. As the flow finally ended, the room was filled with the noises of heavy panting and the faint, muffled whirring as the vibrator shook in Sweetie’s rear.

Sweetie slumped down against Rarity’s chest, exhausted. It was only the sound of Rarity’s voice that stopped her drifting off to sleep. “Now now, little sis. We can’t just have you falling asleep whilst on the job. I know you’ve got more in you. More in those balls.” And without a chance to respond, Sweetie could feel herself being levitated up into the air, before coming to rest between those magnificent thighs.

“You don’t have to tell me twice,” Sweetie exclaimed through a smile and short, sharp breaths. She pushed her shaft against her sister’s quivering vagina, and slowly pressed her way past the folds of flesh.

“Get on it with it dearie! Honestly!” Sweetie was taken aback by her sister’s newfound depravity as she felt a magical grip on her thighs. Suddenly she was launched forwards, hilting herself in her sister in mere moments, floundering embarrassingly as she fell onto her sisters body. Despite the trip the encouragement Rarity had given her was more than enough as her hips began to buck against her sister, practically of their own will. She looked up and stared into her sister’s eyes as she slammed down against her soft, welcoming body over and over again. “Oh Sweetie, you feel so good! I’m so sorry how I shouted at you for… oooh!” Her words turned into a sensual moan as Sweetie began to teasingly rub her sister’s clitoris with a free hoof.

In response Rarity lifted her hind quarters into the air, entwining her legs around her sister’s head. She pulled her sister down against her body, bringing the two even closer. “Rari,” Sweetie gasped through gritted teeth, “your pussy feels so good against me, can we do this every night? Please?”

Rarity focused her vision on Sweetie, giving her a weak smile as every inch of her body screamed for more. “…Of course we can Sweetie, dear, but on one condition.” She leant forwards until her face rested mere inches from her still-bucking sister. “Every time you make love to me, you need to give me another child. Prove to me you are ready for the responsibility of raising your sister’s foals.”

As if in response Rarity felt her sisters cock twitch intensely inside her before firing great jets into her, like the heavens themselves had opened. Gallon after gallon poured into Rarity’s already battered body, pushing past her cervix and into her womb with incredible speed. Sweetie could do nothing but stand there, her hooves gripped tightly around her sister’s sides. By the time that joyous punishment had come to an end, Rarity -to any onlooker - could easily have been ninth months pregnant with triplets. Sweetie - now completely drained of energy – flopped forwards onto her sisters belly, snoring heavily against her juddering belly. As Sweetie slipped into unconsciousness Rarity carefully flicked the switch of the vibrator off. “I think we can forget about the doctor’s advice, we’ve got our own home remedy…”