Rainbow read through all of her borrowed books once again, searching for a clue or something she had missed. It seemed like she'd exhausted all possible catalysts for a breeder bond mark and still nothing. This had to be the right path for them, she was sure of it, but what was she missing? For the first time during this trial, she considered asking for help even though the idea made her physically ill.

Her thoughts scattered as the wall clock chimed. She tapped her hoof on the table next to the open book as if trying one last time to summon a lead before getting up.

Rainbow slunk upstairs. The muffled sounds of the TV emanated through the wall as she neared. The mare knocked softly before pushing the door open.

“Time to get ready for- oh…”

Inside the room the only light came from the flickering screen which dimly illuminated the twins on the bed. They'd fallen asleep with porn on. Pickle was snoring on top of Barley, his cock still stuffed inside his sister's cream-pied pussy. They were already obsessed with rutting just like they'd been with oral, just like they'd been with danger.

Rainbow sighed in the doorway, deciding to just let them sleep as they were and brush their teeth in the morning. She switched off the TV while the scientist was in the middle of her presentation explaining how her new device, the slut ray, could turn anyone into a shameless slut with zero sexual inhibitions. - - -

Pickle woke up the next morning with a hard on which Barley was quick to notice and climb on top of. She straddled his barrel and shimmied backwards, spearing herself on his shaft. The barely awake colt groaned as she slid down to his base and began to twerk her ass with a squelch.

Despite the door being closed, the sound of their passionate lovemaking reached Rainbow’s ears as she finished setting their breakfast on the table. She looked up at the clock and frowned.

“Seriously?” she grumbled. She switched on the kitchen soundsystem by hoof and put on some music to drown them out while she started eating alone. She was completely finished and tapping her hoof nervously on the table by the time they came down flush faced and panting and reeking of sex. They sat at the bar and started to eat their breakfast dazedly.

Barley swallowed a couple of bites of soggy cereal and then looked down to see that her brother's erection persisted defiantly, begging for more attention. How fortuitous; just in time to complete her meal.

Barley got down on the floor and then reared up to wrap her lips around his juicy cock, still slick and tangy with their fluids.

Pickle gasped as he stopped eating. He put a hoof on the back of her head, pushing her all the way down till her muzzle planted between his balls.

“What are you doing?” blurted Rainbow in alarm. “You don't have time for any more; you have to get your saddle bags on and go to school.”

The sex zombies separated, crammed the rest of their food in their mouths and hurried to the front door. - - -

At lunch recess, the twins found themselves wandering the little dirt track beside the bustling playground. They were still a little skittish at school and preferred the company of each other even though they were also the most annoying ponies they knew.

“Wonder when we're gonna get to new material in math,” posed Pickle, loping along.

“Who cares?” shrugged Barley. “It's an easy A.”

“Yeah, but I didn't like geometry the first time around.”

“You didn't do it a first time. We only did like two parts of it back in Hope Hollow. There's a lot more to it we haven't done yet.” She scanned over the playground of foals off in their own worlds and the pink body of Miss Cheerilee moving behind the play structure on the far side. In that moment they were basically unsupervised.

Barley nudged her brother “Hey, wanna sneak off for a minute and rut, ‘cuz I want to.” It wasn't a sultry proposition but an almost clinical one like asking if he wanted to accompany her to the store to get milk.

“Well… yeah, I want to but Rainbow told us not to do it outside of the house,” he warned her.

“Yeah but that's just for safety so we don't offend anyone. As long as we're careful and no one sees us then it's fine.”

“I guess so,” he shrugged. “Probably still shouldn't tell Rainbow though. Where are we going to go?”

“Groundskeeping shed behind the schoolhouse. C'mon.” She'd clearly already scouted the location. The filly fluttered into the air.

Pickle cast an eye behind at Cheerilee and then the foals, making sure no one would witness their vanishing act. Then he took off and followed her. When he rounded the corner behind the school, Barley was standing there at the little shed, holding the door open for him. She motioned with one hoof for him to come. He scampered inside like a rabbit fleeing a wolf. Then his sister let the door close with a squeak behind them.

“Gotta hurry,” whispered Barley but before she could even get the words out, he'd cornered her against the wall and workbench. He smothered her lips with his own, making her practically gush with arousal.

Her rump bumped the wall, prompting her to stand on her hind legs as he continued to encroach on her. He stood up with her, maintaining the kiss and pinning her to the wall. His hoof slipped down between her legs where everything was already drenched and slick. He scooped up her nub and began to massage it rhythmically. Barley moaned into his mouth, her hindquarters trembling in delight. Pickle was fully hard in a matter of moments. No reason to belabor the foreplay with a time crunch.

Barley turned to the side and set her hooves on the workbench, forcing him to back away and set down on all fours. Her tail went up, offering an unobstructed view of the soaked fillyhood he'd already claimed once today. She looked back at him expectantly, not with lust but urgency and a tinge of worry.

Without hesitation, Pickle reared up and mounted her in the semi upright position. He found his target by heat signature, as his girth caressed sideways across her hole. He pulled back a smidge and his tip sprang naturally up into her entrance. He thrust forward as he nestled her body into his. They both gasped.

Wisely, Pickle took no time to settle in. Once he was inside her, he was off to the races, thighs clapping, balls slapping. He rested his chin in the crook of her neck. His hot panting caressing her cheek. The workbench rattled with the force of his pounding. His hoof snaked beneath her undercarriage to find Barley’s fattened clit again, giving it a few strokes.

Overcome with sudden pleasure, Barley let out a cry that she quickly stifled. She bit her hoof, trying to keep the sound of her outbursts hampered to the confines of the shed.

Pickle licked her cheek with a huff of ragged breath. He kept a blistering pace as he raced toward early climax. Barley whimpered into her hoof, her thighs pressing roughly into the edge of the workbench and her front half wobbled on one shaky forehoof.

Suddenly Pickle squeezed her to him as he erupted inside her. He bit his lip to silence his groans while his fireworks finished with several slow but deep, penetrating thrusts.

His sister gave muffled squeals as the hoofjob continued, nearing its resolution. Pickle stayed inside her as he redoubled his assault on her clit. Her back legs shook harder into a crescendo, her body going rigid with bliss. She exhaled with content as her brother pulled out with a squelch and a big drip of his seed splattered on the old wooden floorboards.

“That's gotta be a record for both of us cumming,” she panted, getting back down on all fours. She quickly pulled her beanie straight again.

Pickle was already pushing open the door. “C'mon,” he murmured, motioning her to follow with his head. They slunk away from the shack and back around the corner of the schoolhouse where recess was still in full swing and Cheerilee’s back was turned. They drifted onto the playground as if they'd always been there. The two smiled at each other and smacked hooves.

“Hey, guys,” called Apple Bloom from the swing. “Wanna see who can jump the furthest off the swing? No wings.”

“Okay,” they nodded with interest. - - -

The twins got all their homework and chores done on schedule that day so Rainbow treated them to a movie that they'd wanted to see that was surprisingly from her non pornographic collection.

The three of them sat together on the couch in the darkened living room. Rainbow greedily shoveled popcorn into her mouth as she got lost in the story she hadn't seen for a long time. It wasn't until she heard intimate humming over the dialogue that she snapped back out.

Rainbow looked down to the other end of the couch to see Barley riding cowgirl on her brother's lap. His hooves held her flanks as she glided up and down on his slick pole. They moaned softly, tangling their tongues in each other's mouths.

Rainbow gritted her teeth. She squeezed her own thighs together in discomfort as she quickly became aroused by their spectacle. Then she forced herself to look away and sighed. They seemed to be not only insatiable but unflappable. Maybe they had the stones to be in the next generation of incest porn movies when they grew up, she pondered. They could do it any time, anywhere and probably in front of anyone, including a greaseball director and a camera crew. That was a valuable talent in itself she supposed.

I will totally watch their debut porno feature when it comes out, she thought hypothetically. Does that make me a bad parent or a supportive one? It was a given that she'd be clopping hard to it. The smutty reverie wasn't helping her in her current situation as Barley's moans began to overtake the audio from the movie.

Should she start making them fuck only in their room? Not just because it was more socially acceptable but because she could foresee a coming future where she was perpetually horny and miserable from being around them? Or were such parameters too stifling for their sexual experimentation as they became acquainted with their area of expertise? She needed a parenting book for this very niche parenting journey but she was pretty sure none existed. Maybe she could be the one to write the very first, that is if she could get them their damn cutie marks.

Pickle grunted with carnal satisfaction. Barley pulled off of him and stood up. In the blue glow of the TV screen, Rainbow caught a glimpse of her fillyhood glinting with their combined wetness just before it disappeared behind her tail and she sat back down on the couch next to her brother.

Rainbow swallowed. There was one thing left they hadn't tried and it was definitely a last resort. - - -

The twins burst through the front door as if they had touched down on the doormat from a divebomb. They skidded and clattered on the floor before they could stand by the hooks and hang up their saddle bags.

“Welcome home,” greeted Rainbow with a wide grin. “Juice? I know you're always thirsty when you come back from school.”

“Oh, thanks,” said Pickle, reaching for the glass in Rainbow's left wing.

She abruptly pulled it away and held out the one in her other wing instead. “Here,” she offered aggressively.

Pickle took it in his wing and sipped as he walked to the living room. Barley took hers and followed him.

Rainbow went back to the kitchen and gave the Max Fertility potion double pack packaging one last look before chucking the empty vials discreetly in the trash.

Guaranteed instantaneous pregnancy upon viable insemination. Do not take if under the age of consent.

There was one potion for the male and one for the female and they were color coded black and white. The stuff was pricey but worth the money to put the cutie mark episode to bed one way or another. After they ingested the full contents the rest was just a waiting game. It was a given that the twins would be doing it soon enough. Sometimes they were pawing at each other right there in the entryway before they'd even taken their packs off.

“Can we play a board game tonight?” asked Barley from the other room.

“If you do all the things, we can. Actually if you do your homework now we can maybe go to Sugar Cube Corner today.”

“Yay,” they exclaimed

“But first finish your juice,” she reminded them.

“Okay.”

Rainbow was relieved when they quickly produced two empty glasses and brought them into the kitchen.

“Let's get our homework right now,” suggested Barley.

Her brother silently agreed, fetching his pack from the hook in the hallway. They convened at the kitchen's low table where they spread their projects out and sat on their haunches.

“Let me know if you need any help,” said Rainbow, hovering nearby at the bar with her new book.

They were uncharacteristically quiet and focused for a few minutes, possibly motivated by Rainbow's promises of rewards but it wasn't too long before Pickle stood up again.

“I'm done,” he declared, scooping up his book and papers.

Barley looked up at him with dubious resentment. “How are you done already?”

“I did most of my homework during the story,” he explained.

“Ugh, you're not supposed to do that,” grunted in annoyance.

“But I'm good at multitasking.”

“I bet you didn't hear a single word of the story,” she scoffed, returning to her assignment.

Pickle milled around impatiently, leaving for a brief time but coming back in to check on his sister who continued to read and write studiously. Neither of them knew what to do with unstructured time when the other wasn't around and as a result they'd become antsy and shiftless.

“Hurry up so we can rut.” he grumbled.

“I still have… a lot,” she muttered absently. “Just do me now while I'm working.”

Rainbow's ears twitched.

“Really?” he asked.

“Yeah, I don't need to do anything except stand here. Just try not to be distracting.” Barley got up and draped her front half over the table. Her paper sat before the propped up book in front of her. She flagged her tail to the side, pencil dangling from her mouth as she found her spot in the text.

Already rock hard from the moment she made the suggestion, Pickle inched up gently on her back. He plunged his flare into the heaven between her flanks. He grunted softly as he hilted inside her and their thighs met with a pleasant squeeze. His forelegs kneeled on the table either side of her midsection and he launched into a slow rhythm.

Despite getting rutted, Barley continued onward in her studies, occasionally jotting answers down with her mouth. Her pencil jittered a bit with her brother's thrusts, making her hoofwriting less accurate but still legible. Rainbow kept watch out of the corner of her eye, both out of salacious transfixation and a desperate need for this particular session to pay off. This was certainly a less than ideal way to do homework but she wasn't going to correct them.

Pickle’s mouth was open but his eyes were closed. He kept his head hovering just above Barley's back, rocking their bodies gently with a subdued plap plap plap.

Pickle tried to contain his vocalizations so as not to distract his sister but it was getting more difficult as pleasure quickly welled in his loins, coiling tighter like a spring. On top of that, he was fighting the urge to start slamming her flanks with aggressive conquest. Little by little he crawled toward release until an amazing heat surged up his shaft to his tip, blasting deep into the depths of his sister.

He couldn't help but groan in ecstasy as his cock pulsed, delivering his load. He stood motionless until the blissful sensation faded to a gentle dreaminess.

Pickle sighed and pulled out of her. It wasn't but a moment later that Barley felt a strange buzzing in her flanks that felt different from any sort of sexual stimulation she'd ever received down there. She dropped her pencil in surprise and looked back to see her hindquarters glowing with white light.

Pickle had stopped in his tracks to also look back at himself as the very same phenomenon gripped him. All three of their jaws dropped open in shock. The strange light faded away as quickly as it came revealing a pair of brand new cutie marks.

“It’s- it's our cutie marks,” stammered Barley.

“Yes” exclaimed Rainbow in triumph.

The twins looked back and forth between each other’s flanks to compare. Their astonishment only deepened as they found they seemed to have mirror images of the same mark, an upright wooden barrel filled with barley and a large pickle sticking out of the top.

“We got the same cutie mark?” gasped Pickle.

“Yeah. Our cutie marks are exactly the same. What do they mean?”

“Homework sex aficionados,” shrugged Pickle befuddled.

“I know what they mean,” blurted Rainbow. “Hang on.” She zipped away on her wings and came back with one of her borrowed books from the castle. She opened it to the bookmarked page and slammed it on the table before them.

“You two have a breeder bond. It means your destiny is to breed and rut each other a lot.”

“What?” Barley pulled the book closer. “I mean, I guess it makes sense but what?”

“But we've already rutted a lot,” shrugged Pickle. “Why did it just suddenly happen this time?”

Rainbow cleared her throat awkwardly. “Well… I've kind of been pulling strings to encourage you to do these things and refocus your energy on achieving your true calling and getting your cutie marks because I've suspected that you were an unrealized breeder bond pair for weeks now.”

The twins exchanged curious glances.

“So that's why you kept bothering us to rut?”

“Why didn't you just tell us that's what you were doing?” wondered Pickle.

“Because that feels like a weird conversation to have, especially if I ended up being wrong about it later. And I wanted it to happen at least semi naturally. But, to be absolutely clear, I was pretty sure about it the entire time even though it took so long. Anyway, I gave you both hardcore fertility potions just now and since that was really the only added variable this time, I have to believe that what triggered your cutie marks finally was pregnancy.” - - -

Rainbow successfully infiltrated the Castle of Friendship with her bag of absconded with books. She didn't need them anymore but perhaps Twilight had some others in her collection that would be of use to her in the twins' new stage of development.

In the library, the pegasus hovered high in front of a bookshelf, fumbling through the titles she'd brought. One of them didn't even go in the library; it needed to go back in Starlight's room.

“Hi Rainbow,” chimed a familiar voice behind her.

Rainbow screamed in surprise, dropping her books in a panic.

“What are you doing?” asked Twilight in concern.

She turned around to not only see Twilight but also Starlight and Princess Celestia.

“Uh, n-nothing.” She swooped down to the floor and tried to gather the books.

“Oh, so that's where that book went,” said Starlight, floating the fringe cutie mark book to herself with her magic. “I thought I was going crazy. I knew I left it on my desk… Why do you have it?”

“Looks like they're all about cutie marks,” muttered Twilight. “Oh she just adopted a pair of twins without cutie marks,” she quickly realized.

“How is that going? asked Celestia with a smile.”

Rainbow lifted the stack of books dumbly. “Um… Pretty great actually.”

“So you're trying to help them get their cutie marks?”

Rainbow gritted her teeth and looked away. “Well… No. Actually they just got them so that's why I'm here putting the books back.”

“Oh, what did they get,” gasped Celestia with excitement.

The three looked at her eagerly.

Rainbow scratched her head nervously “Uh… well… see… they… turns out they have… a breeder bond.”

There arose an excited murmur from the trio.

“Oh, how special,” gushed Celestia as if she’d just received a hoofmade Mother's Day present.

Starlight nodded with knowing intellectual assuredness.

“That makes sense,” declared Twilight. “Their genetics and background makes them rife for that.”

Rainbow exhaled. Not only did they all seem to know what it was, they didn't seem to think it odd or lurid in the slightest. She still wasn't sure if she was comfortable sharing the details though.

“It's a good thing they got adopted together. Can you imagine?”

“Good work,” Rainbow Dash. “They're lucky to have you as a mother.”

Rainbow nodded weakly as if considering the thought for the first time. “Yeah… maybe so.” - - -

The morning alarm went off. It woke the twins but was really just a harald to Rainbow bursting through the door.

“Up and eat ‘em, you two; it's sixtynine day!”

The foals rubbed their eyes and groaned as they threw back the comforter. Rainbow shut off the alarm for them.

Now that they had their cutie marks, Rainbow had thrown her full support behind their biologically mandated destiny and had taken it upon herself to give structure to their development with regimented sex training so that they could be the best in their field. She assigned a different position for each day of the week to be completed as part of their morning routine.

With bleary vision, Barley found that her brother was already hard as usual so she climbed straight on top of him, her plot in his face.

“Hold on, Bar, Pickle gets top this week.”

“Oh,” she grunted absently before flipping lazily onto her back.

Her brother rolled onto her, straddling her head, being careful not to put weight on her now visibly growing belly. Then he buried his muzzle into her fillyhood.

Rainbow circled the bed, checking their form from all angles and nodding to herself with approval. “Make sure to swallow everything, Bar; you're eating for two now.”

“Mm-hmm,” mumbled the filly through her brother's cock.

“Hmm… I think you're big enough now that we should probably switch to a sideways sixtynine position for the rest of your pregnancy. We may need to modify some of your other positions as well.”

Rainbow stayed and watched till both twins came and then she hustled them to brush their manes and get dressed while she went back downstairs to make breakfast.

“Got your semen replenishment potion right here.”

“Yay,” said Barley even though Rainbow was passing the drink to her brother. Genetically, Pickle already produced significantly more semen and at a faster rate than the average pony his size but the supplements always ensured he had enough to keep Barley overflowing at both ends no matter how many times they went at it.

Rainbow held up two VHS tapes proudly before the eating foals. “I got brand new research materials for the weekend. New things you've never even seen before,” she teased mysteriously.

“What are they?” asked Pickle with intrigue.

Rainbow quickly obscured the tapes from sight beneath the table before they could even read the titles. “It's a surprise,” she giggled.

Author's Note

And they all smiled warmly knowing that somewhere Scootaloo was smiling down on them...

Ignore the date on the last post and don't be afraid to leave a comment if you have a thought.

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