You lay upon a soft cloudy mattress, literally made of clouds. However unlike normal clouds they were solid and warm to the touch. On this mattress you lay snuggled up to the one and only Rainbow Dash. She seemed to be the only pony who could control herself. Other ponies simply went out of control. Your naked body lay pressed against hers, her soft furry rump was right against your crotch. Your cock lay between those petite blue cheeks of hers, along with her hot marehood twitching against your long, thick cock.
Indeed, your cock has grown considerably larger in Equestria. This helped you in your endeavour to have sex with these ponies. But only to a limited extent, for your cock has stopped growing. Not to mention you did not grow when getting intimate with a pony unlike a stallion. It was a bittersweet thing to swallow when you were having the time of your life mounting a growing mare’s ass, only for you to be left in the dust as the mare’s ass grew far too large for you to handle.
You recalled back on the day you arrived in Equestria. Back then, you awoke in nothing but your underwear. You appeared to be lying on a hard wooden floor. But you weren't paying too much attention to that when the first thing you saw was a pair of comically large blue eyes, which belonged to what appeared to be a pink equine creature. You froze as these big blue eyes looked down at you, you were not sure how to react.
For quite some time you said nothing, and just stared at the equine looking down at you. That was until the equine abruptly turned around and presented you with her rump. Her fat ass was a perfectly round and bubbly rump. You could tell it was a female with her winking equine sex. You don't know what possessed you, but you felt compelled to place your hands upon her cheeks. Your hands immediately sank into the bubbly soft fat of her ass like a squishy pink marshmallow. However, your eyes widened in alarm when her ass began to seemingly inflate like a balloon. The three balloon markings on both sides of her cheeks were clearly an ominous warning, but you did not heed them to your peril.
Before you had any time to react, she dropped her ass down upon your face. You squirmed as she grew bigger and bigger on top of you. The massive mare rolled her fattening cheeks over you; giggling and moaning in pure bliss. Your body became soaked with her dripping marehood, which smelled like sweet bubblegum candy. Your erection came to be snuggled by the warm and soft cheeks of her ass rolling back and forth over you.
The wooden floor creeped and groaned as her ass’s weight continued to pile on. You grunted; struggling frantically to lift her ass, but it was ultimately useless. All you managed to do was sink your hands deeper into the fat of her ass. The mare for her part giggled at your attempts to free yourself from her ballooning ass. If you didn't know any better, you swore her growth rate was increasing from your struggle.
“Hehehe! Mmmm! Oh, please keep struggling!” she said in a bubbly, yet deep voice. Which was only getting deeper the bigger she got. “Oh, and by the way, welcome to Equestria!”
You closed your eyes and accepted your fate but the end never came. Your muscles and bones ached as she continued to get bigger and bigger, but somehow you were never completely crushed. Somehow, you could see her asscheeks pushing against the walls the room; subsequently the fat of her ass became deeply compressed from under the applied pressure.
Her rump wobbled around like a loose waterbed as more and more fat pumped into it without stop. This was your welcome to Equestria, you guessed.
You were taken out of your day dream when Rainbow’s ass abruptly puffed out in size. You started to panic, but your fears were soon put to rest when she reverted back to normal size. This was clearly a warning. She must have been bored from your lack of movement.
You started to thrust your hips against her lovely backside a little bit harder to keep her happy. Still, you hope this would not end the same way it has with most mares. Since it was particularly humiliating when a stallion took your place. Unlike you, a stallion grew larger while having sex with a mare. You could only watch in envy as the hills of sweet mare ass bounced up and down their lap.
You hope that would not be the case with Rainbow Dash today. Figuratively speaking, she was petite for a pony, however the canyon gap of her cheeks was more than enough to swallow your cock between them. Your hands lay upon her cheeks, creating a shallow depression into her soft cheeks, before meeting her ironclad muscles underneath.
Admittedly, you did like the asses of other ponies better. However Rainbow Dash’s ass seemed to be the most stable of the other ponies. Giving you more time to actually have fun with her without you struggling to have sex with her.
You tried having sex with other ponies but things would quickly get out of hand. They would grow so big it was like throwing a hot dog down a hallway for your cock. It wouldn't even make a dent after a couple minutes and left you with blue balls. That was the most unhappy time of your life due to how full your balls felt.
A particularly alarming case was when you tried to have sex with Princess Celestia. This was one of the worst decisions you had ever made in your life. Your body ached at the sheer thought of what happened to it as if your nerves had mental trauma from it. You instantly regretted that decision when you became hit with a massive avalanche of snowy white ass. Leaving you crushed under pure musky darkness as you struggled against the several tons of weight. She practically exploded like a nuclear bomb in growth. The protection magic slowly cracked like a shield under it and started to form holes before her butt crushed you under its immense weight without mercy. It took you a week to recover after that, despite the weight protection magic all ponies have. Your body was broken and many of your bones were moved out of place. Leaving you in agonising searing pain all over your body. If it wasn't for the slow healing magic the ponies have, you didn’t think you would ever be able to walk again after such an ass slamming down on you.
Most other ponies were far less explosive in growth, and even quite slow. Though this didn't really mean much due to the power of their growth. Even if it was slow they would grow several feet per minute; even the slowly growing ones didn’t really last very long. Oh, sure, they would start off even smaller than you, but that wouldn't last long as they grew in size, but within the space of a few minutes, you would be dealing with an ass that you could not handle. Leaving you completely crushed like you were with Celestia. Unable to move and forced to have the ponies bounce on your body and use you like a dildo. You were not even able to thrust back due to how many tons of weight were on your body. Leaving your bones creaking and groaning due to the weight on them.
Regardless of their slow growth rate they were prone to growth spurts as well. Just yesterday, you managed to have sex with Fluttershy for a good few minutes. The little yellow pony had such cute moans and groans from your thrusts. The clapping of her cheeks was so hot and it left your cock throbbing and begging for more. Her growth was particularly slow. Meaning you were able to have fun with her more due to how slow her growth was. Her ass would gradually balloon at a snail’s pace, allowing you to have sex with her with relative ease. The feeling of her ass growing on you made you more and more horny. Your heart thudded in your chest as he continued to thrust in and out between her slowly growing cheeks.
But then, after a while her growth began to abruptly accelerate. Going from a couple inches every 10 minutes to a couple feet per minute. Leaving your cock in the dust due to the size that she was growing too. Her ass would come slamming against your hips as it became flooded with sudden migrations of fat pumping into it; gurgles and groans filling the air as a loud whooshing filled the air which signifies her growing more and more. She would become embarrassed at this.
Fluttershy blushed as she continued to pant hard and fast as her tongue had lolled out of her mouth due to the pleasure she got from growing.
You tried your best to continue to have sex with her. However, it was a losing battle, your cock was slowly, but surely filling the mare less and less as her rump continued to get fatter and fatter. Leaving more and more room for her to grow faster and faster. You whimpered as you tried desperately to continue filling her as best you could with your cock. A few more minutes later her next growth spurt would become even more volatile. Sparks of light pink magic flying off her body along with her wings going out in a rigid manner. Standing up and almost hitting you in the face with its size. You found yourself slammed backwards as her ass ballooned like a hot air balloon. Slamming into the wall with a loud boom and cracking it behind you as you were squished into it.
Fluttershy stared back at you, her face bright red in embarrassment. Her eyes sparkling with embarrassment as she tried to close her eyes and not look at you. Concern with how her human was doing was the only thing allowing her to keep her eyes open and staring at you. Her massive rump dominated your vision, towering over you like an oversized queen's mattress. Casting a massive shadow over you and keeping you pushed into the wall behind the bed you were on. You gave Fluttershy's ass a good worship before parting ways with her. Giving it some kisses and rubs with your hands as you lay there.
Your hands lovingly caressed her air ballooning cheeks. Your cock moved back and forth between the growing canyon of her buttcheeks, her marehood becoming ever more distant as you became more and more inadequate for her size. You imagined she couldn't even feel it due to how massive her butt was now. Your hands were barely able to cover a small amount of her rump due to how big it was. Your hands sank into it like it was quicksand as it slurped up your hands. Nonetheless she reassured you with comforting words and moaned even as her ass reached truly epic proportions. It was nice of Fluttershy trying to reassure you with her loving words and bounces of her butt against you.
Her warm and buttery soft buttcheeks squeezing your cock worked like a makeshift vagina. Giving you an immense amount of pleasure as your whole body sparked from the pleasure going through your body. Your whole body shivering and shaking as you panted heavily while fucking the butt in front of you. Her cheeks jiggled widely about wildly with a meaty slab each time a sudden growth rocked her form. Each thrust seems to cause her growth to go even faster and faster. Each new growth became stronger than the last. There were more and more sparks flying around the air and hitting the walls, causing some of the paint to fall out of it while doing so as her ass continued to balloon as you worshipped her.
You were left by more and more in its shadow as you worshipped her rump. Fluttershy continues to grind and bounce her butt against you; lighting clouds of power starting to form around the mare and sparkling with power. The ground became hit with echoing booms of magic as you continued to fuck her ass. Her growth began to accelerate even further, and what was left of her home became bulldozed down; turned into dust under the several tons worth of pillowy yellow rump leaving nothing left in its wake. A massive hole in the ground was made, which was the size of her cheeks as the house turned to dust with booms and crashes.
Her head came crashing through the ceiling with a loud boom and her buttcheeks rolled over the ruins of her home, crushing it into a fine sawdust. Pieces of the ceiling flying through the air and landing several miles away in Cloudsdale and on the mountains along with the villages around. Ponies looking up and jumping away as the ceiling of Fluttershy's house lands onto the ground and breaks through houses. Even several nearby trees of the Ever Free Forest became knocked over by her ballooning cheeks. The trees were subsequently crushed into a fine dusty powder; making a huge mess of the local area and causing clouds of the dust to float around the area and formed into clouds. Blinding any creature that tries to see the growing ass coming towards them.
Her ass continued to get larger and larger, eventually reaching the point it was basically like a grand American Football Stadium of ass you were worshipping. Massive amounts of the forest was cleared by the behemoth mare. Being broken apart by this force of nature which was expanding into them. hundreds of creatures from the forest desperately scattering like dust to the wind as they ran away. She wasn't going to stop growing as her power continued to grow more and more with each foot she grew.
You were tempted to worship her even more. However, you began to hesitate when you heard Fluttershy snoring. The mare continued to get larger and larger in her sleep, but your motivation to continue greatly diminished, for the giantess mare had fallen asleep. You pressed on for a few more minutes and watched her ass get bigger and bigger in her sleep. But you began to feel so inadequate before the mighty sleeping mare. You now do believe she only moaned just to make you feel better; causing your cock to deflate in size.
You sighed; shaking your head as you crawled out from under her butt and coming out with a loud pop.
With that, you ceased your worship of her butt. You pulled your cock away from the loving embrace of her warm and soft cheeks. Once you parted ways with Fluttershy you saw, like all ponies, she gradually began shrinking down in size. It appeared ponies only grew from affectionate stimuli. Leaving you surrounded by ponies looking at you in confusion before sighing. Going back to what they were doing as they had shrunk to their normal size now.
Upon leaving the remains of Fluttershy's Cottage it seemed to fix itself out of thin air. Even the fallen trees outside her home seemed to sprout out of the ground. Slowly reforming as tendrils of wood formed and creaked as they combined. Turning into more trees as the leaves burst out of the wood and flowers grow out of the ground as well. Curiosity got the better of you and you decided to open the door only to be greeted by the massive fat ass of Fluttershy. The giant mare appeared still to be asleep, she was slowly shrinking down in size. Though her power stayed even after she was getting smaller. The interior appeared to be larger than her own cottage exterior. Leaving you baffled at the size but deciding not to question it. From your time here you had decided not to question the ability of the ponies around here. There was clearly some other wordly magic at foot. It seemed the power of the mare had decided to manifest in a pocket dimension of some sort, which made sure that no damage would come to any pony around her as she grew from the worship you gave her. Your curiosity satisfied you left the place, quietly shutting the door behind you.
That was until, a familiar large red stallion came walking up to you, the one and only Big McIntosh; casting a massive shadow over you as you slowly turned around. Looking up at him in awe as his red skin bulged and pulsed with his muscles. Your heart sank at the sight of him. The musk that came off of Big Mac filled your nostrils and made it so you can't smell anything else. You could see the stallion slowly inching upwards into the air before you; magic pulsing across his body and sparking with loud echoing booms which shake the area. You could see his massive black stallionhood between his legs swinging about wildly as it rapidly grew outward in growth; his balls underneath inflating like balloons. The balls of Big Mac gurgling and sloshing violently with balloons of virile cum. His long, thick cock bobbed up and down as he grew inch after inch by each passing second. The muscles of his body began to bulge out, his strength becoming enhanced.
“Ah am sorry, but a mare can’t be left unsatisfied,” he said, his voice becoming deeper and more masculine by the second. The growing of his muscles seems to correlate to his voice getting deeper and deeper. The voice of Big Mac getting more and more deep with each second and each pounding of his heart. When he finished speaking he abruptly spurted with growth into the air, becoming a massive bulking stallion about the size of an elephant. the hooves of his creating great gashes in the ground and making a huge mess of the nearby area. The muscles of Big Mac writhing and pulsing like worms with each movement of his body.
You watched the stallion walk past you; the door automatically enlarging itself to allow the massive stallion access to her cottage. A great orange glow covering the door and letting out a groan as the doorframe grows. His cock throbbing and bobbing heavily under him before pulsing and slamming into his chest with a thud. Letting out massive drops of couch sized pre which slam into the ground and melt the area under them. He then came to stand behind Fluttershy’s massive rump. Another growth spurt rocked his form, his cock swung about wildly slapping against her fat cheeks with a loud meaty slap. Fluttershy’s cheeks clapped with the loud meaty slap upon his cock slapping her cheeks.
Her ass jiggled about wildly as it began to balloon once more in size; upon receiving stimuli to grow from Big Mac.
Meanwhile, Big Mac became a towering giant of a stallion, with a cock that might as well be a skyscraper like the Empire State building. You watched him position his gargantuan cock to the entrance of her sex. In one quick motion he pushed his cock inside her and immediately began thrusting. You could see Fluttershy's rump air ballooning bigger and bigger as he slammed into her. You were left in the dust and shamed as Big Mac rode her brains out. Fluttershy moaned loudly as her growth skyrocketed. You became firmly pressed against the door as her ass grew against you. You grunted as you struggled to break free from the embrace of her ass pushing against you. You tried to slip out the door but there was no escape from her ass.
To make matters worse there seemed to be divine intervention intervening. Since you found yourself forced to watch Big McIntosh mount Fluttershy even as her ass pressed you against the door. You could see his massive stallionhood ploughing back and forth against her; her rump jiggling wildly with each thrust. The door spontaneously behind you became replaced with an all too familiar snowy white ass. It squeezed you into the growing body of Big Mac and Fluttershy which made you groan. You felt your body being crushed a bit between them but you were unharmed.
Princess Celestia giggled as you were forced to watch the spectacle, her white ass ballooning against you. Making sounds like a balloon which shakes the whole room with sheer volume. Celestia was clearly enjoying herself as her juices started to flood more and more. Making the whole area smell of a mix of green apples, lemonade, and orange juice from the mixed juices. Leaving your senses swirling with the amount of scents and musk filling the air. You were now firmly trapped between Fluttershy and Celestia's ass. It will probably take hours before you will be released; making it so you could barely move due to how squishy their butts were.
Back in the here and now, Rainbow’s ass still seemed to be remaining stable. Keeping its normal size to your surprise due to most ponies growing from your cock going in and out of them.
There was no growth in sight. Though you were still enjoying the fucking you were doing of Rainbow; pleasure arching up and down your body from the sexiness of the mare while your balls slammed into her butt. Rainbow on the other hand seemed to have grown rather agitated. Perhaps her trying to not grow was a real struggle for her. Some sweat went down her brow and dripped to the floor from her concentration. The mare trembled against me with her tail swishing back and forth against my body. I could see her teeth were firmly clenched and her eyes were firmly shut.
Rainbow sighed; dropping her head down upon her pillow. Clearly she had given up the fight with stopping the growth of her butt. Your heart jumped up in your throat as you struggled to hold yourself together from running away. Sweat dripped down your head as you sat behind Rainbow with her butt towards you. Your worst fears then came true when her ass puffed up like an emergency car air back against you. A loud whoosh filling the air as her butt expands and sends out sparks in the air with loud booms to the sudden changing in the air. A loud meaty slapping sound could be heard as her fat cheeks clapped together from the resulting migration of fat pumping into her ass. The blue rump of hers rapidly inflating and growing in front of you which left you in awe as it rapidly grew into you. You were now presented with two big blue beach balls of her asscheeks. Gone was the petite mare, now replaced with a bootylicious mare; who’s rump was only getting bigger by the second as it inflated like a hot air balloon. Leaving your cock more and more in the dust with its rapid growth and making you more and more inadequate to please the mare.
“Sorry, dude. I could not hold back any longer,” she said in a guilty tone. Clearly she did not want this to happen since she wanted you to enjoy it as much as she. Rainbow was blushing and panting as her butt grew and more nerves filled her butt which caused nerves to spark pleasure all throughout her body. As she spoke her ass continued to jiggle about as more and more fat pumped into it; creating a wondrous meaty clapping sound. The sounds of her clapping cheeks were almost deafening due to the growth of her shaking cheeks. Her ass moving around like a tsunami slowly growing through the time of its movement.
You did your best to have sex with Rainbow Dash as long as you could but her ass just kept getting bigger and bigger; causing you to whimper and pant heavily as your hands covered less and less of her rump. You tried desperately to hang onto it with your hands but felt them sink deeper and deeper. Leaving you ever more and more desperate while kissing her ass and playing with it. Your cock was filling her less and less as her rump inflated against you. Your body getting pushed back farther and farther due to her growing butt and being surrounded by her growing ass around you. The gap of her buttcheeks eventually became so thick that you could only hot dog your cock between those ballooning cheeks.
You sighed in defeat. There was no escape from growing pony ass, even from the most athletic mares. Such was life for you as the only human in Equestria after all. Since you would never be able to fuck them for very long as they outgrew your cock. Some would do it slower then others but you would always be inadequate for them. You sighed in defeat as you were slowly crushed by the growing blue ass and got forced into the floor. Feeling it crack from under her weight as you were forced into bliss. You blushed and panted deeply as you continued to hump her butt and got pre all over it; starting to cum over and over from the sheer amount of pleasure from the growth of her ass. Leaving your cock more and more in the dust as you worshipped her ass as best you can.
Just then you heard a loud thudding sound. Magic thudding in the air and sparking around as a spell activates. You could only react to the magic by trying to move away from it. Not sure how it will affect a human like you due to not having magic back home. The cloudy mattress beneath you began to shake. The clouds of the mattress turned into a dark grey before loud thunder filled the room.The walls of the room began to stretch out to accommodate the arrival of a larger pony. Big McIntosh came into the room, and positioned himself behind Rainbow Dash. Leaving you stunned due to how big the stallion is above you.
He was bigger than ever before. You were absolutely left in the dust due to his size. Your mouth drops open in shock at the thick veins on the cock above you throbbing with the heartbeat of the stallion. The movement of his stallionhood shook the whole bed which made you bounce up and down with each thud of his cock and balls. The balls of the stallion sloshing and gurgling as the cum within sloshed around like a mini tsunami as you watched. His cock might as well be the arm of a galaxy, his massive balls were like the event horizon of two supermassive black holes on steroids. And he was still growing, you could see the veins along his cock pumping with power as it gained thousands of inches per second.
Rainbow Dash moaned, her growth beginning to accelerate; her ass rising to attention. Giving the stallion more to breed due to her getting even bigger and bigger. She spreads her wings in excitement as they flap a bit in pleasure due to smelling the musk of the balls of Big Mac. Drops of pre-cum from Big Mac came falling onto the floor with loud wet booms which flooded the floor with the thick viscous white liquid.
Rainbow’s blue cheeks rose into the air like two twin galaxies. They jiggled and clapped as massive amounts of fat pumped into them. You became smothered under an expanding sea of blue smothering you upon her cloudy mattress. Leaving you unable to move any longer as blue magical sparks flew around you as Rainbow's cutie mark started to glow with the amount of power she is gaining.
Your mattress soon became replaced with something even softer. The magic sparks coming off of Rainbow falling onto it and making it glow with the same colour. Clearly this sort of thing was at least planned out due to the magic the mare had on her. Not like you could do anything to stop her at this point due to how big she was compared to you. It was some sort of yellow squishy soft material. You could feel your new mattress actively pushing you into Rainbow Dash's ass as it seemingly inflated in size. With magical intervention, you could see there was something far outsizing both ponies, a truly gigantic mare, an all too familiar mare: Princess Celestia.
You could see Rainbow Dash’s asscheeks were sitting down on only a small fraction of the spiralling sun of her right cutie mark. Rainbow was like a tiny spec of blue surrounded by a sea of yellow.
You could see her cutie mark stretching outwards around an ocean of snowy white, her buttcheek. The much larger mare acting as a fucking bed for the couple above you which only forced you to worship the ass of the two. The massive amount of musk flooding the air overriding your senses and turning you into a lust filled machine. Her cheek wobbled wildly as massive amounts of fat pumped into it. Massive tidal waves raged across it, becoming larger and more volatile by the second as her cheeks continued to air balloon in size. The buttcheeks of Celestia glowed like a sun in of itself and even having an atmosphere to allow you to breathe.
“Oh, you know, human, our growth was not as violent prior to your arrival. It was much more stable. We even shrunk in size at a much faster rate. But, now, me and my kind will consume this universe and beyond. All will be smothered under our fat asses. A new age has come, the time of the pony has come. I Empress Celestia will lead us to a new golden age of peace and love.”
You could see Celestia was no longer withholding her growth. Her whole body glowing in a bright white glow which was almost blinding. Though you were still able to see and were not instantly blinded due to the power of Celestia. You were left a blushing mess due to how big Celestia was getting. The human brain is not meant to handle such beauty and just turned into a mush of pleasure and constant orgasms. Already, a vast amount of the universe was consumed by her. Planets, stars, black holes, and galaxies swirled into her mouth as she gorged on them with gluttony; slurping them up like meatballs and spaghetti as she moaned in pleasure due to them exploding in her and making her grow even faster.
You could see Empress Celestia was gathering a massive army of her ponies upon her ass. Seeming to climb out of her fur as it rippled like a pool while they assembled up in lines. Forming up into ordered ranks as they took their first few steps and had their first few thoughts in their lives. Many a pony were growing larger to answer the call of their Empress. Although, it was not entirely equal. Some of them were left behind in terms of power and size as they grew at different rates. Some grow metres per minute and some only grow several feet per minute. The vast majority of ponies grew to truly epic proportions were the mares; their rumps air ballooning violently in size. However, most of the stallions were left in the dust, and even became smaller; their cocks shrivelling up in size. white magic covering their cocks and slowly getting smaller and smaller like a reverse cycle of a banana growing in time-lapse. Stallions like Big McIntosh were an odd exception to the rule, most had pitiful penises, average being about three inches long even while erect. The balls of theirs sloshing and gurgling with cum even though they had gotten smaller.
The lesser stallions could only cry as they were smothered under greater and greater amounts of fat mare ass. All of their cutie marks glowing and pulsing with power as they grew. Creating craters in the ass of Celestia which was above them due to their growing size. Though Celestia didn't really seem to notice due to her constant growth and the growing size disparity. Their tiny penises constantly ejaculated prematurely upon their ballooning cheeks. The cum that they were letting out only covered a mere speck of the rumps above them. The cum got soaked into the fur of the mares like a sponge which only made them grow even faster. Not even being noticed by the growing mares due to how big they are. Even the stallions dwarfed you in terms of cock size which left you even further in terms of being unable to please them. You were left laying there and continuing to hump as best you can with your small cock.
Newly captured aliens found themselves under the shadow of massive mare rumps. Getting forced to worship their growing asses and cumming onto their butts as well. The aliens try their best to please the mares but having their sizes and power stolen to feed the growing mares. The ponies left no cock unshrunk and no breast and butt size not stolen to add to their infinitely expanding bodies. They seemed to be even further down in the pecking order, they became even more pathetic in size and their penises only became an inch long. You could only look on in horror as your penis rapidly shrunk down in size. Sparks flying around your cock and getting covered with it due to the power of the mares all forcing it smaller.
“You shall have the honour of being the most pathetic male. Your cock won’t even be an inch long,” spoke Celestia’s booming voice. Echoing across the vastness of space and shaking the very fabric of reality. Several hundreds of nebulae being knocked out of where they were before Celestia sucked up the nebula. Drinking them down like a nice soup As she smiled to herself at her growing body. Shockwaves formed due to the power of Celestia's voice alone as it ran along her several sun-sized vocal cords which only accented her size. Spirals of the galaxy being forced out of alignment from the massive black hole at the centre of the galaxy
Your cock shrunk down further in size until it might as well be a tiny toothpick. You could feel it painfully ejaculating prematurely constantly against Rainbow Dash's ass; all the while Big Mac's glorious and growing cock pounded her ass with greater and greater fury. Creating massive shockwaves along both the mare's butts. Celestia's ass jiggling and moving around like a tsunami which shook all of reality with the force. Cracking it and creating tears in it but not breaking it just yet as it struggled to contain the growth. Big Mac continuing to ceaselessly fuck the butt of Rainbow Dash which clapped and moved around like a palm tree in a storm. Her tail moving back and forth as she moaned and panted loudly from the pleasure sparking up and down her body like electric currents.
Suddenly Rainbow Dash’s ass ‘pulled’ away from you. It was like you were being sucked into a blackhole as you were dragged away against your will. You whimpered as you came again uselessly into the air. Being surrounded by a black goo which slurped you in and sounded like you were moving through honey. It stuck to you in clumps before it fully sucked you under into the goopy mass. In reality you saw it was pushed back by a light grey see-through sphere of magic; in which you were free to move at your leisure. Leaving you a bit flabbergasted as you took deep breaths. Having panicked a bit from being sucked into the sphere against your will. The floor underneath you also became replaced with a sphere. You could see Rainbow’s big blue ass pushing against it from above. The sphere felt like lukewarm gooey material against your body.
The sphere was a few hundred miles tall, and was slowly growing in size as it pushed upward against Rainbow’s ass. At your feet it pushed down against Celestia’s ass. Both Celestia’s and Rainbow fat asses folded around the sphere, encasing it in a bubbly ass prison. A deep depression was created from the applied pressure, forming massive deep pits in their asses on both sides. You were then given a glimpse on a molecular level that this sphere was actually made of microscopic ponies; who seemed to be both magical and mechanical in nature. These tiny ponies replicated like bacteria, growing in number.
You simply stood there, not sure what to do. Until a dull grey pony submerged out of the floor. She was quite small, about the size of your average four foot tall pony… before growing. You watched the pony smile at you, her dull grey eyes turning into a rosy red eye colour and her coat becoming a light cyan blue… and her mane and tail became a rainbow… She became Rainbow Dash.
“Allow me to introduce you to my grey goo ponies. You shall become well acquainted with them,” Celestia giggled.
This new grey goo Rainbow Dash turned around and shoved her buttcheeks against your crotch. Your tiny micropenis found itself hugged by her blue cheeks on both sides; the length was so insufficient that it was not even able to reach inside her marehood. Undeterred you placed your hands upon her cheeks and watched them sink into the soft bubbly fat. And then an all too familiar thing happened, her body began to grow bigger; her buttcheeks pushing against your crotch. Except this time you didn't even have the dignity of entering her vagina before her growth went out of control. All you could do was hump helplessly with your tiny penis between her fattening blue cheeks.
To add further humiliation another grey goo pony materialised in front of Rainbow Dash. This one took the form of Big McIntosh. He pushed his hips forward and brought his cock into Rainbow’s mouth, who promptly began to suck it off with vigour. Technically, she was being spit roasted by you and Big Mac, however you only had a tiny toothpick of a cock between her buttcheeks, while he had a massive log of cock. You could see her neck bulge with a massive amount of cock going down her throat.
You attempted to pull away from the humiliation, only to feel something pushing against you from behind. You could see that it was pink in colour. You knew that ass, it was Pinkie’s ass. Pinkie Pie giggled pushing her ass against you; forcing you to hot dog your cock between Rainbow Dash's cheeks .Rainbow grinded her soft rump against you as she feverishly slobbered on the cock in front of her. She squeezed her asscheeks together, forming a tight seal for you to press your tiny cock between. With Pinkie Pie pushing her ass against you, and Rainbow squeezing her cheeks together you were imprisoned, and forced to hump her ass with your small penis.
You could feel their asses pushing against you as they ballooned in size. Out of the goo below sprouted a massive black stallion cock. You could only look on with envy as this new cock came to plunge itself between Rainbow’s cheeks. Rainbow moaned as the stallionhood expanded between her cheeks, increasing in thickness and length. You could only groan as your tiny painful erection spattered tiny dribbles of cum between her cheeks.
The massive tip of the black stallionhood soon came to rise out of the deep canyon gap of her cheeks. It rose like a mighty black obelisk of cock between her asscheeks. Rainbow wrapped her tail around this mighty stallionhood, wrapping in the warm softness of her rainbow tail.
Just then, a second black stallion cock rose out of the goo below. This one came to rise between Pinkie Pie’s buttcheeks. The mare welcomed this cock with a giggle, and snuggled it with the softness of her cheeks.
You found yourself completely humiliated. For you were smothered on both sides with big fat pony buttcheeks, and your absolutely pathetic tiny cock only reached a measly distance between the great chasm of Rainbow Dash's cheeks. Said chasm became deeper as her rump air ballooned in size; you could feel the great migrations of fat pushing against your body as it grew. The two great big black stallion cocks became bigger and bigger between their cheeks. The great stallion black cocks were enveloped by their ballooning cheeks; snuggling it on all sides. You were left in the dust as you saw those two mighty stallion hoods become bigger and stronger by the second.
The cherry on top of your humiliation was Rainbow uttering muffled moans while slobbering down on the cock pushing further and further down her throat as it grew in size. Her body was able to bend and twist in order to accommodate the massive leviathan of cock growing inside her. Her neck bulged to an uncanny degree with the sheer mass of cock pushing down into her.
Just then two more great black cocks rose out of the goo below. They reached out like the tentacles of an octopus to both Pinkie and Rainbow's marehood. The two mares crane their necks back as they moaned as yet more cock came to love them. The massive pillars of black stallion cock grew into their needy marehoods.
You sighed, this was your fate. To be humiliated by big fat pony asses. You could only partake in the bittersweet feeling of your hands caressing Rainbow Dash’s fat cheeks pushing against you, and the warm and soft feeling by being smothered from said cheeks. Your pitiful cock constantly and painfully ejaculated between her cheeks, only causing her ass to swell further as tiny nanorobots consumed your cum; and repurposed as more fuel for her growth.
All the while this was happening, you could see Celestia’s smiling as she consumed the entire universe and began to enter the multiverse to eat that too, and maybe even beyond at some point. You could see the great legions of her ponies bouncing their growing asses upon lesser ponies and small aliens alike.
This was a butt of all things.