In Twilight's Bedroom, two of your former small pony friends have really become more like horses than actual ponies in terms of size. They were nearly as large as Princess Celestia herself, who was standing on the bed right over you, her large body casting a dark shadow over you.
“That penis of yours sure is doing some weird ass shit to us Anon.” said Rainbow.
“Indeed. What other affects could Anon’s penis have on us?” inquired Twilight, rubbing her chin thoughtfully.
“Whatever the case may be, it seems to be positive with you two being alicorns now.” said Celestia, gently stepping off the bed onto the floor. “Unfortunately, I must attend to my duties now. Please, let me know if more changes happen to your bodies.” she said, lighting up her horn with golden light, summoning a large, floating black box over her genitalia, before she vanished with a flash of light.
Now, with Celestia gone it was just you, Rainbow and Twilight.
“So, ummm… want to try out your new sex organs?”
“Buck yeah! I want to see what more awesome things your penis can do to me!” said Rainbow in a raised, excited voice, nearly shouting.
Twilight sat down, then summoned a piece of parchment and a quill with a flick of magic from her horn. “I shall document this historic day for Equestria.”
With that Rainbow stepped unto the bed. Her massive body towering over yours, casting a dark shadow over you.
“Uhhhh… Rainbow… you’re a lot bigger now…. and uhhh... heavier.” you spoke nervously.
“Oh yeah, right.” she said, blushing bright red. “Twilight, could you give us a hoof here?”
Twilight flashed her horn, briefly enveloping your body with a lavender glow, a light tingling sensation coursing through your body. “There. That should stop you from hurting him.”
“Thanks Twilight.” she said, before gently sitting herself down on your lap.
You uttered a loud grunt upon feeling her heavy backside making contact with your pelvis, but other than her great weight, you felt no pain. You raised your arms, just barely reaching her cutie marks upon her massive backside, your hands sank deep into the thick layers of squishy soft fat.
You groaned, at the feel of your rapidly hardening shaft rising between her two huge, soft, pliable mounds of her rump’s cheeks.
“Uhhh, Rainbow. Can I do you from behind?” you inquired
“Oh, sure Anon.” she said softly.
Rainbow stood up, you following along with her. You took hold of your shaft, guiding it toward her marehood… only to meet a problem. She was too tall, your penis could only reach between her upper legs. Through this awkward moment you heard Twilight make a quiet squeal, before hastily writing something down on her parchment with her quill.
“Rainbow, I can’t reach.” you said, nervously.
Rainbow stepped off the bed, presenting you her backside from a slightly lower level at the foot of the bed.
“What if you do me up there?”
“Okay, but make sure I am protected from falling.”
Twilight flashed her horn, enveloping your body with a brief lavender glow, a slight tingling feeling going through your body. Once done, she went back to her notes, watching anxiously for your next move.
Rainbow stared back at you with warm, loving eyes. You smiled at her, before taking hold of your long and thick, horse-cock like penis, resting the tip against the plump lips of her marehood, wet with rainbow coloured cum, her musk giving off a strong scent of skittles.
You moved your hands to the sides of her luscious, big blue rump, your hands sinking deep into the thick layers of soft fat, before reaching the hard, firm muscle deep beneath.
Without further ado, you roughly pushed forward into her tight, hot depths, pushing a full quarter of your shaft into her, the powerful walls of her marehood squeezing your shaft almost painfully tight as you did so.
Rainbow let out a loud yelp, tears falling down her cheeks. Twilight gasped in shock, before hastily scribbling something down.
“Rainbow, are you OK?!” you asked softly.
“I… think…. I’m a virgin again Anon. So, please, be gentle.” she said in a pleading tone, staring back at you with adorable, puppy dog eyes.
“Sorry Rainbow. Do you forgive me?” you said softly.
Rainbow nodded, despite hissing in pain and the tears falling down her cheeks like a waterfall.
You gave her some time to adjust to your violent entry, before slowly beginning to push into her deeper. However, once you began Rainbow literally began to cry like a baby, filling your ears with loud cries of pain.
“Rainbow! Do you want me to pull out?” you shouted.
“Nu-no. Keep going, I want to lose my virginity… again… with you.” she spoke in a low voice.
Your heart ached seeing her in such pain, nonetheless you pressed onward, trying your best to ignore her cries. Slowly and gently, you pushed into her, your shaft slowly disappearing into her squeezing marehood.
You tried to do something to distract her from the pain, by gently rubbing your right hand over the wide surface of her massive backside, while moving the other to her lower back to give her gentle strokes repeatedly. Rainbow for her part didn’t seem to notice, the pain was just too much for her to handle.
When your tip reached as far as it could go, she let out a loud muffled scream of pain into her hoof.
You simply held your long and thick shaft deep inside her, awaiting for her to stop crying before doing anything.
Several minutes went by, before Rainbow spoke, her massive eyes badly bloodshot. “Anon... do me like your human mares.”
Tenderly you pulled your shaft back to the point of nearly exiting her, before gradually pushing into her. Rainbow let out low whimpers of pain, tears falling down her cheeks as your shaft went into her tight, squeezing marehood.
Once you bottomed out you slowly pulled back, before again slowly making your way into her again.
Back and forth, you went into her with utmost gentleness. What seemed like forever, you tenderly made love to her, her whimpers slowly turning into low moans and quiet horsey sounds.
Despite, these new sounds coming from her you continued to make love to her gently. Your shaft gently pushing back and forth into her repeatedly.
Until you heard the magic word. “Faster.” she breath, panting heavily.
From hearing that word, you began to pick up a little speed. Your large balls now lightly slapping against her backside each time you thrusted into her.
You moaned and groaned in delight, the hot, wet and soft walls of her vagina tightly squeezing your cock was simply incredible.
Her squishy soft rump felt awesome to the touch. You payed homage to that big blue ass, by squeezing and rubbing the smooth surface all over, watching in delight as her flesh deeply depressed like soft dough under your applied pressure.
“A lot faster!” she shouted.
You pulled slowly back, before slamming hard into her, your balls making a loud smacking sound against her rump. You barely managed to hold back your laughter when she made a loud squeaking sound like a dog’s chew toy.
Like a well oiled machine you thrusted back and forth into the hot, squeezing walls of her marehood without stop. Each time your hips made contact with hers, your balls made a loud slapping sound against her fat rump, and the soft fat of her backside rippled like jello from the hard impact, Rainbow moaning aloud and making loud neighs and other horse noises as you did so.
Twilight's quill and parchment fell out of her shaking hooves, no longer being able to take her notes at the sight of you riding Rainbow like there’s no tomorrow. From there, she proceeded to feverishly rub her marehood, moaning aloud and making loud equine sounds.
The room became engulfed with the sounds of flesh slapping against flesh, moans, groans, and quiet horse noises.
Unfortunately, all things must come to an end.
“Oh, Rainbow. I’m about to cum!”
“Yes! Fill me up Anon! Love me like a human woman!” she shouted excitedly.
With a loud grunt you unleashed into her, spurt after spurt of your creamy human spunk shot into her, your hips grinding against her through your release. Rainbow made loud whinnies, rainbow cum flowing out of her vagina like a river, your white cum mixing with it.
Your shaft like a continuous volcanic eruption fed her more and more seed into her, you screaming like a madman. The wonderfully soft, tight walls of her marehood squeezing, and your non-stop release of cum was driving you insane with lust.
“Ooh ooh ooh! Eee eee eee! Aah aah aah! Aaaaaaahhhhhhhhhheeeeeeeeeeee!” you roared, literally making monkey sounds and angry chimpanzee sounds as you fucked her.
Rainbow gave you a worried look, but allowed you to continue to ravage her backside as you made crazy ape and monkey sounds.
Your twitching cock continuously releasing into her with wave, after wave of your creamy essence, the feel of her soft, powerful marehood squeezing your shaft, the soft feel of her rump’s cheeks depressing deeply from under your grip, and the sight of her fat blue rump jiggling wildly about each time your hips collided into her made you lose your mind with lust.
Rainbow made loud whinnies, her tongue lolling out of her mouth as you continued to ravage her backside. A huge pool of both your white cum and her rainbow cum formed beneath you, the liquids mixing together.
Eventually, your cock gave one last spurt of creamy human spunk, your shaft now slowly softening inside her, and you stopped making those crazy sounds. But other than that, Rainbow appeared to not have undergone any changes.
“Damn Rainbow. You drive me crazy.” you panted, gasping for breath.
“Anon, you can make chimpanzee sounds while you ride me any time.” she said softly, looking back at you with a loving look filled with warmth, her cheeks blushing profusely.
“What the buck was that Anon?!” Twilight shouted, raising her two front hooves high into the air.
The End
Author's Note
A short sequel. Not sure where to go from here. Feel free to expand upon this story with sequel or a spin off rewrite of your own using this universe's concept.
