Zira loved Ponyville. Ever since she’d arrived, selected by her tribe to attend Twilight’s School of Friendship, she’d wanted everything to do with the new culture that she found herself immersed in. Everything was different from her homeland, from their family structure, their houses, even the food they ate; but the ponies had always been kind to her and the other students, despite being from various different lands, and Zira had always admired that.

Zira found herself taken in by an eager pair of siblings in Ponyville through a residency program at Twilight’s school. Rumble, a colt about her age, had spent the first couple weeks pestering her with all sorts of questions about her home, sharing with her his video games and toys, and introducing her to all his friends. Thunderlane, the older brother and caretaker, was always making sure she was comfortable. He cooked delicious meals, even the not-so-accurate renditions of cuisine from her homeland. Their home was full of love and they’d welcomed her into it without a second question. It was truly heartwarming, and Zira was delighted.

She spent the year studying hard to learn the ways of pony friendship to bring back home with her to her herd. They were eager to learn about what she was being taught and to share that knowledge, so she wrote letters often.

One thing that always struck her, though, was how ponies treated the ones they loved. In Ponvyille, Zira had been surprised to see and learn that ponies only had one mate, and usually stuck with them for life. This sent shockwaves through her little mind like an affront to everything she had been told! Back home, in the herd, one usually had multiple mates and they openly expressed their love at will. Here, Ponies were so stuck up they scarcely even kissed each other in public.

Months passed from her initial arrival and she slowly acclimated to the new culture. Rumble had become her best friend, chatting with her every day about what she’d learned or heard. Often, they would stay up far into the night, talking, reading one of his goofy comics, or playing video games. She had grown a special soft spot for him. Thunderlane always checked on them before bed, making sure she had whatever she needed, whether it be another blanket,—her homeland was much warmer than Ponyville, so she was always cold—a glass of water, or anything at all. She’d gotten used to his constant intrusions and slightly overbearing nature, and passed it off as just another pony quirk.

Fall grew into winter, and she experienced her first snow with fascination. She learned about Hearth’s Warming and delighted in pony holidays and traditions.

Then, before she knew it, winter grew into spring. A week after the annual Winter Wrap Up, with which she’d participated gleefully, Zira awoke in a cold sweat. The first thing that came to mind was that she’d fallen ill. After all, it wouldn’t be the first time during her stay in Ponyville, as the winter flu had caught up with her a few months prior, but it was the strangest. She didn’t feel a fever but her body was hot. The blankets were itchy and warm, so she kicked them off. Her body felt heavy and sluggish. She was dripping with sweat, and there was an aching, itching need somewhere between her legs that she just couldn’t place. A knock to her door caused her to jump with a start.

“Time to get up, Zira! Breakfast is ready!” It was Thunderlane, speaking with urgency through the door. “Almost time to leave for school!”

“Ugh, I’m not feeling so good today, Mister Thunder.” She called back, “I think I might be sick!”

“Uh-oh, that doesn’t sound good. May I come in?” The door creaked open and Thunderlane poked his head in without waiting for an answer.

She pulled the blankets over herself, suddenly feeling very self-conscious. As Thunderlane walked in, his large stallion body nearly blocked half the door frame, blocking out the light from the hallway. He moved by the side of her bed and looked around the room, taking a deliberate whiff.

Something immediately washed over him and his eyes grew to the size of saucers. He gazed down at her, looking up and down her form with a face of complete surprise. His tail twitched behind himself, revealing his slight agitation. Zira pulled the covers closer once again, feeling feeble and strange.

“Zira, I think I see what’s happening here.” Thunderlane reached out and put a hoof to her forehead to check her temperature, fully knowing it was a pointless gesture. He swallowed dryly.

“What is it?” She wiggled and squirmed, feeling the scratchy blankets graze her skin. They briefly made contact with her thighs and she shuddered.

“Didn’t... didn’t your family ever talk to you about the birds and the bees?” Thunderlane was nervous, starting to back away. She blinked dumbly at him.

“Uh...about Estrus? Or where foals come from?” He looked into her eyes hoping for some recognition behind them but she just continued looking confused. Thunderlane sighed and took a seat at the edge of her bed, being careful not to sit near her. Her scent hung heavily in the air, and each time he took a breath more and more of it wore away at him, permeating his thoughts.

“Sweetheart, you’re in heat...” he began, “and when a mare is in heat, it is to show she’s ready to take a stallion and have foals, so to speak. Except your body does this whether you’re emotionally ready for a foal or not, and it’ll make you think and act differently. It’ll wear away in time, after a few days.”

“But...I don’t want it to take time! I want it gone now!” She was fidgeting more, eyeing him up and down. “You’re a stallion, can’t you help me?”

“What? Nonono—this was a mistake. I better go get Cloudchaser, o-or Zecora, and of them can--” He started backpedalling farther, getting up from the bed. The smell of needy filly was heavy on his mind now, his member starting to slide forth from his sheathe despite the conscious part of his brain screaming at it to stop. Zira, for her part, started to tear up like she was about to cry. She threw off the covers and for a split second Thunderlane saw it; her reddened, engorged and puffy filly slit, bordered by tufts of striped fur, with her pert little tailhole nestled underneath. Small droplets of aroused filly juices were forming on the outside of her vulva, mixing with sweat. She saw the way he looked at her, how he subconsciously licked his lips, transfixed, and it made her fillyhood wink hard, pushing out her little pink button and clenching her whole walls, making her let out a loud squeak.

“Eeek!”

Thunderlane kept backing up. He bumped into the door, nudging it closed accidentally. It slammed shut, leaving the two of them alone together. It was the last straw to break his resolve. Something inside his head snapped.

“Zira, I... shouldn’t do this.”

“Please,” she whined, “it hurts.”

Thunderlane took a few steps forward. His member dangled conspicuously between his legs. It was nearly the size of her hoof.

“Wow! Is that your thingy? I saw stallions with them all the time back home, but yours is big! And...” She reached down between her legs, sitting upright, and spread her fillyhood open. She winked again, causing a bit of juices to squirt out, and squeaked. “I-it goes in here?”

“How did you know that?” Thunderlane was nearing the bed, a forehoof on the edge of it.

“I saw it. Back home. They didn’t know I was watching.” She grinned mischievously, sweat still dripping from her body. “So, will you help me?”

Thunderlane started climbing up onto the bed. He towered over her, in size and nearly every other aspect. Crouching down, near to the source of that delicious, intoxicating smell. He took a long whiff and exhaled, his hot breath tickling her nethers, which earned another strong tremble from the filly.

“You have to promise that this stays a secret. Just between us.” His tone had changed, less one of worry, or that usual caregiver style he had. Now he was talking to her like a mare he was about to mate with, his voice dripping with lust and desire. His eyes were half-lidded as he gazed longingly at her body.

“I promise!” Zira squeaked, wiggling her hips. “Just help me, please!”

Thunderlane’s inhibitions finally broke down, and there was nothing left to hold him back. He buried his muzzle in her winking slit and lapped at it hungrily, dragging that warm, wet appendage from the bottom of her rump up between her filly lips and flicked at her nub at the top. Zira clenched down, lifting her rear as high as she could. He was just about to bury his muzzle in her delicious honeypot for round two when a voice caught his attention behind him.

“...Thunder? Zira?” Rumble’s voice was unmistakable. Thunderlane knew what his face would look like before he’d even turned around. He was busted: done for. Rumble would tell everyone. How could Thunder betray his brother like that? He’d seen the looks Rumble gave her, had kept his distance to let their feelings blossom, and now he’d gone behind his back...

Instead, Rumble’s eyes were wide and filled with hunger. He took a sniff of the air, then another, and another.

“Whoooa. What’s that smell?” He walked toward the bed, eyes sparkling when he saw Zira, leg’s spread, her saliva-dripping fillyhood winking once again, and he was lost in himself. He clambered up her bed without invitation.

“It’s Zira. She’s in heat. Listen Rumble, I was just--” Thunderlane started to ramble.

“Can I join? I mean, if it’s okay with Zira.” Rumble looked at her snatch hungrily. Zira nodded meekly, desperate for release and satisfaction.

Thunderlane couldn’t believe his ears, but he wasn’t going to second guess anything that was happening. Before anyone else could speak he dove right back into the wonderfully tight and burning hot fillyhood. He slithered his tongue up between her lips and wiggled it into her walls. The filly immediately gasped and bucked her hips, but he held firm and true.

Rumble moved to her side, his own little colthood quickly hardening. Zira seemed to get the hint, and with a little encouragement, moved her hoof to touch it. She curled her hoof around it and massaged Rumble’s much smaller shaft, pumping him up and down at a gradually increasing pace.

Thunderlane’s tongue had wiggled up through her canal, pushing deeper than anything had ever explored her before, making her feel tingly and warm in parts of her she didn’t know existed. Craving more, she clenched her hind hooves around his head. Despite this, he pulled back from her dripping privates.

“Sit near her head. Maybe she’ll give you a blowjob if you ask nicely, little bro.” Thunderlane encouraged the little colt and went right back to licking and lapping at the squirming filly.

Rumble did as was suggested, scooting further up the bed. He was level with her head by the pillows, his trembling little colthood dangling in front of him, desperate for attention.

“Z-zira. Will you... I mean, if you want to. You don’t have to. But I’d really really love it if you might—” Rumble was cut off by her warm lips wrapping around the tip of his penis, bathing him in her breath, letting her tongue swirl around his member and sampling his taste.

The constant slurping and dancing of Thunderlane’s tongue was beginning to have a new effect on Zira. Her head felt dizzier and she was trembling more than she had been before. Holding up her hips with his forehooves, muzzle buried in her fillyhood, he started eating her out with loud slurps and suckling noises. She closed her legs around his head, lifting herself higher. That warm and fuzzy feeling in her tummy grew and grew like a balloon until she felt ready to pop. Her body grew lighter and she arched her back, accidentally sucking in more of Rumble than she meant to when suddenly her whole bodyclenched and spasmed and she came all over Thunderlane’s face and chin.

Zira’s continuous slew of squeals and moans were muffled considerably by the colt dick in her mouth. Rumble had swelled up to be a lot bigger, in a state pure bliss as he let her move her lips up and down his length at her own pace. It was the most incredible sensation.

Fillycum dripping from his chin, Thunderlane pulled back and sat up. Zira felt much better—that overwhelming heated sensation and itching deep in her core was mostly gone, but there was still a very faint, but persistent, need. She looked up at Thunderlane to see his enormous stallionhood on full display, and he was pointing it right at her. Or more accurately, her private area.

Where some fillies might have shied away at the realization of what was about to happen, Zira was no ordinary filly. Though she knew little of mating or her body’s own urges, she recognized that mating was something for ponies that loved each other and happily shared themselves, and Zira trusted these ponies next to her who had been nothing but kind and loving. She spread her legs willingly for Thunderlane and watched him passively while her lips worked Rumble’s shaft with more focus and attention.

Thunderlane, still barely able to think clearly through the thick cloud of musky estrus scent, didn’t stop to think about whether what he was doing was right or wrong. He was purely driven on instinct. He lined himself up, the tip of his cock lightly slapping her lower lips. With a hoof on her belly to hold her there, he pushed in. She had some inclination that it would hurt, but Zira wasn’t prepared for how bizarre and full it suddenly felt. He penetrated into her with one swift motion, spearing into her opening and spreading her wide, wide apart. If his tongue had explored newfound depths and made her feel a whole new world of wondrous sensations, his enormous cock was carving it’s own through her body, forcing her to accommodate and stretch, and felt like a whole new universe all of its own.

She had nearly completely forgotten about Rumble. Her eyes shut tight as she fought through the discomfort. Rumble grew impatient, hooking his hooves behind her ears and started to hump her muzzle. Zira obliged him, letting her tongue hang free so he could do with her as he pleased.

Meanwhile, both of Thunderlane’s forehooves planted firmly at either side of Zira. He angled his hips and plunged into her again and again, repeatedly thrusting into her depths. Her inner walls rippled and squeezed him like a vice, pleasuring him beyond compare.

“Oh my goodness, Zira. So. Tight.” Thunderlane moaned as he found a steady rhythm and picked up the pace. “I’m not gonna last much longer.”

“Me, neither!” Rumble quipped, curling over her head and ramming into her throat. “Her tongue is awesome!”

Zira could merely let out muffled sounds, grunt and gagging noises as the two stallions kept up their momentum, and she couldn’t be happier. She was in pure wonderful bliss; that deep, aching need in her core was finally being sated, like an enormous fire that was about to be quenched.

Hooking his forelegs around her hips and hind legs, Thunderlane began thrusting at a higher pace, pounding her poor, stretched fillyhood repeatedly. Before either colt or stallion was able to cum, Zira felt the metaphorical balloon finally pop, sending her over the edge and practically exploding into a fit of spasms once again. She clenched hard and came all over Thunderlane’s thick member, squealing fits of pleasure into Rumble’s.

Rumble doubled down, his little cock shooting a series of short bursts into her mouth and down her throat, some of it dribbling down her chin, before rolling off. Thunderlane was far harder to please, picking her up and pinning her underneath of him, slamming into her like he was rutting an adult mare. He cried out, his member flaring, locking them in place. Zira squealed and came a third time as he filled her womb and overflowed her pussy with his virile seed, burst after burst of it shooting deep inside her and leaking out of her tunnel.

When they’d finally stopped spasming and squealing drawn-out orgasms, all three fell into a heap of pleasant afterglow. Rumble and Zira snuggled up together, smooching, while Thunderlane spooned, member still lodged deep within Zira.

“Do I still have to go to school today?” Zira asked, breaking the silence long after Thunderlane’s penis had deflated and exited her, her head cradled under Thunderlane’s neck.

“I suppose not,” Thunderlane laughed, “you win. Now, who wants ice cream?”

Both foals jumped up.

“Me!”