Based on a fantastic recent picture by PussPuss on derpibooru #1480936

And a second great picture by lunarmarshmallow #1497895

Chapter 1 - Rainbow's Rough Morning

Up on a particularly well built cloud sat a beautiful and cozy cloud-house. This particular cloud-house belonged to a certain very fast pegasus by the name of Rainbow Dash. At the moment, Rainbow Dash was not sleeping as comfortably as her otherwise luxurious cloud mattress and 500 thread count Saddle Arabian sheets should have allowed.

However, her groaning, twisting and turning in her sleep was not due to any nightmare. If that were the case the guardian princess of the night would have seen to it that this element bearer's sleep would be resolved quickly, allowing her to sleep unimpeded. No, these particular types of dreams were left alone by Luna, else she find herself accidentally drawn into them... though Luna sometimes found that a fun experience in itself, she tried to avoid embarking in such proclivities with ponies she knew well (like Rainbow), lest things get awkward the next time she saw them in person.

However, if she did happen to peek into Rainbow's current dream-state she would have seen quite the erotic sight:

Teenage Rainbow was racing about her Cloudsdale home, incredibly pumped that she'd been admitted directly into the Weather Service right out of Flight School.

"Mom? Dad? Come quick, I've got the awesomest news!" Rainbow shouted as she zipped around her home, looking for her parents.

"In here, hun!" Rainbow heard her father in the kitchen and she zipped right in. "Your mother's out right now picking up dinner, whats all the fuss about?" Bow Hothoof questioned, as he leaned back in his kitchen chair.

"You won't believe it Dad, I got accepted into the Cloudsdale Weather Service! Just got the confirmation letter and everything!" Rainbow chirped happily.

"Incredible Dashie! I knew you could do it! Come over here and give your father a big hug!"

Dash zipped over and wrapped her hooves around her Father's barrel, looking lovingly into his eyes as the tone of the scene shifted suddenly. Rainbow's conscious mind was on complete autopilot, unable to intervene as her body's desires took over.

"I love you Dad..." Rainbow said huskily, a strange mixture of daughterly love mixing in with burning teenage lust.

"I love you too sweetheart, gimme some sugar." Her father's manly musk and strong jaw were suddenly irresistible to the teenage pegasus. Both adult and teenage Rainbow would have been mortified if they ever looked over Bow Hothoof's muscular upper body while biting their lower lip and feeling their most feminine body parts begin to moisten.

Rainbow leaned in to plant a kiss on Bow's cheek, but partway to his mouth her head twisted and she opened her muzzle to allow her father's thick tongue entrance as they engaged in a deep french kiss. In her dream state, she was unable to think about the awkwardness of feeling her hot teenage snatch begin to heat up and drip teenage-filly cum onto her family kitchen's floor while she deeply inhaled her father's familiar odor and sucked at his tongue.

Similarly, her brain wasn't functioning properly enough to realize that this dream had strayed far from the original happy memory, as her father grinned and said in his usual gruff but dad-like tone: "OK hun, you better turn around so I can buck your little fanny senseless."

Teenage Rainbow, panting even harder than she had after she'd taken first place at the Flight School track finals, spun eagerly around and raised her flank in the air while moving her multi-hued tail out of the way, exposing her squelching, winking teenage slit.

"That's my girl! You did so well, I'm gonna reward you by pumping you full of cum until you make a big mess on the floor!" Bow chuckled, his tone as familiar as if he was giving Rainbow a raise in her allowance, despite the horrifyingly different script.

"Really!? THANKS DAD!" Rainbow squeaked as she wagged her winking rump in front of her father. A squirt of juice spattered out and splashed to the floor. Rainbow smiled as though this was the most normal thing in the world.

She felt her father's rough hooves on her shoulders as he mounted her, the texture familiar from one time she'd asked him to give her a back massage when she was younger and had strained her wings training. She'd never asked him to do it again because of how embarrassed she was when she'd started to heat up a little bit during that massage... now her father was about to plow her marehood and she was grinning like an idiot.

She looked back to see her father's fat cock extend from its sheath - somewhat accurately remembered from a time she'd seen it in the shower when she was younger. She'd never seen it throb to such a full, hard and erect state like it was now though. She shuddered in eager anticipation as she saw it lift and drip pre-cum from its tip as her father squeezed his muscles to lift the fat cockhead to her waiting and open teenage folds.

He bent down to her ear and nipped gently at her lobe as she smelled his familiar fatherly breath again. She snorted and whinnied slightly as he did this, eager for him to take her.

Sensing this, Bow nipped harder. Suddenly and violently he pressed forward, thrusting deep into his daughter's teenage filly-hood.

Strangely, Rainbow didn't feel any pain or discomfort, even though her semi-conscious mind knew that at this point in her life she was still a virgin when she'd graduated flight school. Instead of feeling scared and pain-filled she was enraptured by the feeling of her father's thick cock as it smashed halfway deep into her body, her teenage snatch twisting and gripping at her father's stallionhood.

Her heart shaped clit winked out again and again, each clench rubbing her cute love-bulb along her dad's dark blue cock. She groaned out loudly as he continued stuffing her teen snatch, going a little deeper each time as he pressed his hips toward hers.

"Dad, dad, dad, daddy! Can you go a little faster?" Dash huffed as she felt her clit jamming against her fathers medial ring again and again. Each thrust to go deeper into her young and immature body being blocked by her father's rather impressive girth.

"That's my number 1 little girl! Always wanting to go just a bit faster!" Bow chuckled happily as he began to thrust faster and harder.

"Unf, unf, unf, yessssssss..." Rainbow groaned as she felt her teenage cunt pour sloppy juice all over her father's lower shaft and balls as her body let loose. The added lubrication finally let her swollen bulb slide up and over the medial ring of her father's dick, making her squeak in shock and lose her breath as the remainder of the thick cock slid into her clenching love sleeve. ""Wow Dad! You're bigger than Soarin'!" Dash chuckled, her unconscious mind once again ignoring the impossibility of young teenage dash being able to compare her father's cock to a future fling's size.

"Nothing but the best for my number 1 little girl!" Bow's grumbling voice came out as he reached his hoof down and pawed his daughter's small teenage teats.

"Dad, stop! Not my teats, they're ticklish!"

"Oh? Don't touch those? How about this then?" He shifted his hoof up to her tight little ponut, making rainbow quiver and start to pull away.

"Yikes! No! Not my ass!"

"Language young lady, what word do we use in this house?" Bow scolded as he continued slamming his daughter into the floor, his heavy stallion balls slapping up against her squelching lips with each deep thrust.

"My butt?"

"Try again?" Bow cut her off as he slapped her tight teenage flanks, setting off another mini-orgasm that led to her hot, tight, twisting teenage cunt gripping and swirling around her father's swollen dick.

She blushed in embarrassment, she was a teenager now, she hated using filly words... but still she murmured out "...my tushie.".

"Good girl! That's my number 1 little girl!" Bow whinnied as he hilted deep into his teenage daughter's body, her now fat and sloppy lips squelching around the base of his big dick. His entire stallionhood was now wrapped up by his precious daughter's filly-hood, so hot and wet and churning.

Rainbow felt her hips bucking back into her father in spasms, then her wings flit out into a full erection as her mouth dropped open. Her aching cunt began to loose a steady stream of filly-cum which ran down her father's hilted erection and dripped from his balls onto the floor.

She felt her uterus puckering and convulsing as she began to cum even harder., her walls trying to milk her father's seed into her body. She moaned out loud as her dad bit deeply into her neck and tugged at her mane before releasing and saying in a normal tone to her:

"That's my number 1 little girl! Your pop's gonna fill you up now so you can give him lots of healthy foals!"

She felt his stallionhood begin to jerk and spasm, and her body wanted nothing more than to feel the sweet, warm, sticky release from its yearning to be filled with her father's cum, to be his broodmare and bear his foals, to have a fat pregnant-teenage belly while she drowned in his hot sticky juices until she lost her mind thoughts of ball-slapping, cock-heads, flares, kissing, sperm, dicks, penises, spurting, squirting, juices, splatter...

~~~~~~~~~~~~
Rainbow awoke with a start, her body soaked with sweat and her bed and sheets a complete mess. It took her a second to catch her bearings and remind herself that she wasn't a teenage filly, that she was the head of the Weather Division in Ponyville, that she was a Wonderbolt active duty member... and most importantly that she wasn't getting fucked senseless by her dad.

That being said, as she took stock of her surroundings, she couldn't help but feel the soaking wet nature of her sheets below the waist, and her still aching and burning nethers.

Rainbow threw her head back against her pillows in frustration as she realized what was happening. "Ugh I hate heat dreams! Scratch that, I hate estrus altogether!" She threw off her blankets and got up, wringing her pungent and wet tail onto her balled up sheets. "Sooo embarrassing... my own dad!? Thanks a lot, brain!" Rainbow groaned as she tried and failed to erase the memory of her father's pulsing cock in her throbbing vagina out of her mind.

She threw the sheets into her hamper as she stumbled through her house, the sun having already risen a while earlier "Estrus dreams are the worst! They never finish you off either, always leave you hanging so you want to run out and bump uglies with the first stallion you run into."

She walked into her bathroom and ripped open the medicine cabinet as she continued grumbling to herself. "I thought I had at least two weeks before my estrus would start, too! I know I'm always early but sheesh, this is pushing it! Must have been all that extra sun I got... now where is it..." Rainbow shoved various pill bottles around before seizing upon a particular purple potion bottle with a crescent moon logo and a foal-proof cap. She eagerly undid the cap and upended the bottle into her open mouth and outstretched tongue... only for nothing to happen.

"Argh! AND I'M OUT OF MOON TEA!? Great, just great!" Rainbow slapped her wing against her forehead. Moon Tea was an essential medicine for all mares in Equestria. It had a two-fold effect: suppressing the powerful biological urges and physical reactions brought on by estrus in mares so that they would not feel compelled to rut every living male in sight until receiving their desired load of semen... and acting as a powerful contraceptive in case any mare should choose to engage in some sex while in estrus. Rainbow took a moment to remember how she'd drained this bottle before shacking up with Spitfire, Soarin', and Thunderlane for 4 days of raunchy debauchery during her last heat.

"This just gets better and better... now I'll have to start my day with a cold shower and a run to the Ponyville apothecary." She turned on the cold water tap from her cloud-based shower, turning the stream as ice cold as she could handle it and doing the only thing she knew could help at this moment. Taking very much the same position she'd just held in her dream (and causing her to think once again about Bow Hothoof fucking her teenage self senseless... thanks a lot brain...) she presented her plot to the freezing stream and shuddered as the ice-cold water poured over her aching clit.

"This sucks." Rainbow groaned.

A few minutes later, Rainbow was bounding down her stairs, grabbing her saddlebags as she went before a noise from her living room caused her to freeze.

"H-hello?" Rainbow craned her neck over the banister to see who was in her home.

A very familiar blue pegasus put down the picture she was looking at and turned happily toward Rainbow. "Hi Honey! We were just passing through on our way out to Appleloosa for the cherry pie pairs eating competition and thought we'd drop in to say hello and maybe grab some breakfast with our number one daughter!" Windy Whistles, Rainbow Dash's always chipper and energetic mom intoned happily.

Rainbow Dash felt her stomach drop. "Is... is dad here too?" She looked around nervously. Windy Whistles walked up to Rainbow while she adopted a concerned look on her face.

"Of course, honey! He's just outside organizing the luggage, why whatever is the mat-" she stopped as she got close enough to Rainbow to smell the tell-tale musk that all mares knew. Scrunching her nose up at the smell, she zipped over to Rainbow and began fussing and inspecting her daughter. Before Rainbow could stop her she lifted Dash's tail and checked how swollen her labia were.

"Oh! Oh my. Is it quite bad dear? Why haven't you taken your moon tea? Did you already take it and its still bad? You always did have the worst heats, starting from when you were a little filly right up until after your teens, I used to have to have a whole shelf dedicated to ice-packs for your little fanny you'd get so swollen up. Do you remember that time your father got a black eye and put one of your ice-packs right on his muzzle? He asked out loud what that smell was and you turned as red as a cherry!" Windy giggled as she inspected Rainbow's plot one more time before her daughter snapped her tail between her legs.

"Mooooooooom," Rainbow groaned, "you're always so embarrassing!"

Windy couldn't help herself and kept on. "Oh don't be such a baby, let me tell you something just between us girls..." she leaned in close to Rainbow and nudged her with her elbow, "that scent got him so fired up and perky that evening that I needed the ice-pack for my little tush the next day!" Windy said laughing.

"MOM, seriously. Stop! So not cool!" Rainbow's blush only got to another level as a familiar voice and face burst through the door.

"Hey Dashie! How's my number 1 little girl!" He called as he pushed past the living room and into the kitchen with an armful of his and Windy's luggage.

Rainbow almost choked as her mind zipped right back to her dream when her father had used those exact words in that exact tone before thrusting his thick cock into her aching teenage vagina.

"N-nothing!" Rainbow awkwardly responded, causing both Windy and Bow to look at her sideways.

"A-anyway, I'mreallysorrycan'tstickaroundneedtoruntalklaterbye!" She squeaked as she escaped to the front door. Unfortunately, as she paused to open the door and fly away, her body betrayed her, knowing that her father was looking in her direction...

Mares in estrus would sometimes refer to their marehoods as having a separate mind - they did the darnedest things at the most inopportune moments. In this case, Dash's body unconsciously 'showed the goods off', her tail flicking up and to the side as her vagina, now exposed for all to see, gave a mighty wink, parting open her glistening folds and nearly squirting. For any mare, this was always embarrassing, even when done for their significant others, for dash to essentially 'flash' or proposition her father, she was ready to crawl in a hole and die... at least she managed to resist squirting, but a second rapid fire wink forced a small drop of her potent grool to fall to her floor, with an audible drip.

"EEP, OHMYGOSH gotta go!" Dash kicked the door open and took off, the sonic boom rocking her house as she shot away into the distance.

"What the heck was that about?" Bow asked as he turned from the luggage he had been arranging, not having noticed his daughter's winking marehood being flashed at him.

Windy chuckled and walked over to the door where the drop of her daughter had fallen, quickly placing her hoof over it so he wouldn't notice. "Oh dear, you'll never understand us mares." She laughed as she wiped the juice up with her right hoof with a stealthy shuffle.

"Haha! Ain't that the truth... come here snuggle bun!" He reached out unexpectedly and grabbed Windy's right hoof and leaned in to plant a kiss on it like a prince to a princess as he did sometimes, before leaning in to kiss a blushing and wide-eyed Windy. "Honey, are you wearing some type of a different perfume this morning? I won't lie, you're making me feel like a horny little colt right now." He gestured between his legs toward his groin, and Windy looked down to see that his cock was slowly growing out of his sheath and filling. Windy chuckled internally as she remembered the rutting she'd been given the last time Bow had accidentally gotten a big whiff of Rainbow's musk.

Windy leaned back and grinned at Bow. "Let's get you upstairs big boy, you haven't been this excited in ages..."

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Author's Note

This is my first multi-chapter fic, and the second chapter will include the piece of the story with our protagonist anon making his entrance.

Let me know if you like/enjoy in the comments so I know if I should continue or not!