“Wow,” April said in an impressed manner, “The teachers really can’t see us in here!”

She was a foal with soft pink fur, shortish orange hair and soft blue eyes, definitely a filly from the little slit her round belly ended in, right before the anus. The pony accompanying her, her friend Copper was a golden furred colt, with grape purple hair, and blue eyes. Neither had their cutie mark yet, as each was only 9 and 10 years old, respectively. He was looking at that slit with interest, but April hadn’t noticed.

“Yeah, so I wanna show you before they come looking for us,” he said hastily, “My big brother had his special somepony over, and they were doing something that looked really... good. It was because she was a mare.”

“What were they doing?” April asked curiously, from within the bushes where they were hiding, the dappled sunlight laid along their coats as it filtered through the leaves overhead.

“He was...” Copper blushed, “He was touching her. In the... place you’re not supposed to touch, under her tail. It made me want to... touch her too.”

“Did you?” April asked in wide-eyed shock, “What did it feel like?”

“I–I didn’t, no,” Copper said in apology, “But you’re a filly. I can’t touch a filly down there, without having... you know, a filly. I don’t have a little... slit down there. I just have... colt stuff.”

“O-oh, I never asked, but that must be weird,” April said nervously, “What’s it even... like? How do you pee?”

“Um, with my penis,” he said, “It comes out, so I can... you know.”

“I just pee with my um... slit,” April said, blushing as she did and raising a hoof, “What’s it like having a penis?”

“Well, it’s been getting bigger lately,” Copper said thoughtfully, “And... and my brother’s was getting *really* big, so I guess it’ll really... I mean it was just hanging between his legs. Then he um... s-so he touched his special somepony under her tail, and... it made me want to do it too. I’ve never felt down there before, and I was wondering if I could maybe... touch yours?”

“It’s weird, we’re not supposed to touch down there,” April mused, planting her hoof, “But that’s the only place you and me are different. I’ve never touched a... a penis before.”

“You wanna?” he asked hopefully, swishing his short-cut purple tail. Then blushing, he said more conservatively, “I mean you know you can, if you want.”

“W-what’s it like?” April asked nervously, “Is it really... fuzzy?”

“It is kind of fuzzy,” Copper agreed, “There are two... balls down there by my sheathe. You can... feel them if you want, but they’re kind of sensitive, so no hooves okay?”

“You want me to... lick them?!” April asked in shock.

“Well um, you don’t... have to—”

“No, no I want to it’s just... weird,” April said, “I can just... lick under there and you don’t mind.”

“As long as you don’t lick my butt hole,” Copper said cautiously. At April’s blush, he said, “And I’ll... lick your filly place too. A-and I don’t even care if you poop out of your butt, just don’t do it on me.”

“I would never!” she exclaimed, “Do you think that’s why they don’t want us touching down there?” 

“Maybe,” Copper replied, “But um... recess isn’t that long, so...”

He turned his rear her way, and April approached with caution. She’d never seen a colt’s balls up close, if balls was what they were called. She wasn’t supposed to look down there, her mommy said a lady doesn’t stare and April stared. It was weird! The colt didn’t have a little slit, just one puckered butt hole, and then smooth golden fur down to his little scrotum hanging there so invitingly.

“This is kind of cool already,” April declared in fascination, “I can just... look at you down here and we won’t get in trouble. You look really... cool!”

“Thanks,” he said, blushing bashfully, “You can touch, too.”

“I wonder what it feels like,” she said indulgently. 

“Me too,” he said, “But go ahead and touch it first, I can wait.”

She nosed up against his balls. They slid away within his scrotum at her touch, her snout spreading them apart as she smelled the colt’s... strange spicy scent from his velvety soft ballsac, that made something... happen between her legs. She felt excited down there, like squirmy and antsy, the more she breathed in his musky scent.

April didn’t even hestate to lick his balls. The smell was making her feel... wild, and uninhibited. She tongued at his ballsac, nudging the little balls in it around, as the colt said, “April, it’s going to—! I can’t stop it coming out so... nnh.”

Then before her eyes, her friend unsheathed, his dark penis sliding out and expanding right in front of her nose, as she laid eyes upon it, drooping between his legs. “Sorry,” he said, “It... wants to come out sometimes.”

“Can I touch it?” she asked reverently, looking at the thing gleaming in his sheath’s sweat.

“Yeah,” he said a little tensely. April nosed at it, then just immediately wrapped her tongue around it. The foal was amazed to feel it throb underneath her tongue, tugging away from it. It was even softer than his ballsac, and entirely furless. The flat head tilted away from her, until it was at half mast, where her tongue could only ineffectively explore it.

“I–I need to... touch you now,” Copper said anxiously, “I really want to... lick under your tail, where your... slit is. R-right now.”

“It feels funny back there,” she said uncertainly taking her tongue back to herself, “Your penis is making it all... tickly. W-what if I’m ticklish down there?”

“I won’t do anything if you’re ticklish,” Copper assured her, “But my brother’s fillyfriend really liked it, so I think it’ll feel good.”

“Okay,” she said, wanting it on a level she didn’t quite understand. “It makes me want you to lick it too,” she confessed, “You can just... go under there and lick me any time. I–I want to feel it, and... I actually know what a boy feels like.”

Wide-eyed, April declared to her friend who faced her, “Copper, I know what a boy feels like! I didn’t even know what a penis felt like, and you just let me feel it! It was really cool, and I want you to find out what a filly feels like too, n-not that there’s anything under there, since I don’t have a penis, or balls. But I think you’ll like it.”

“Turn around then,” he said, “And lift your tail.”

April did, and... underneath her tail, she felt the colt nosing around. “Try smelling,” she said as her hind legs stiffened with urgency, “Does it make your penis and balls feel funny when you smell me?”

“It does,” Copper said distantly, “I think my penis is getting bigger. I-I’m gonna do what my brother did, to you.”

“What did he hnn!” she started to ask, but her groin announced itself boldly as she felt Copper press his tongue up against her slit. She wanted to say something, but the strange flowing intensity from there was so strong, she just braced there and panted, while he pulled her back there, and pushed his tongue harder against her, and moved her around back there.

He released her from that overwhelming attention then, and her tail just about jerked out of the way as he climbed on her rear, and bore down on it, hunching over as she stared back in confusion.

“Copper, what are you...?” she asked breathlessly.

“What my brother did,” he said tightly, hugging her flanks in a way that made April shiver and face forward, her hind legs spreading apart, because she... she wanted something back there. “I need to touch your fillyhood with my penis,” he murmured nervously.

“You what??” she hissed a whisper, then her mouth fell open, as she felt *something* touch her back down there. April looked back again, staring at her own ass in disbelief, as Copper seemed rather preoccupied, pushing the head of his penis against her little pussy in a *really* weird way. “You’re...” she said in fascination as he pushed against her then slipped and rubbed alongside her, giving a grunt of dissatisfaction as he pulled back sliding along her belly to push the head against that aching need in her rear. “You *are* touching it with your penis.” 

Then Copper pressed against her even stronger this time, and she squeaked, as something... slipped open back there, and his penis immediately slid in, making April’s entire butt feel like it was stretching. She snapped to staring forward again. She *had* to, as her unknown instincts to be bred took her over, breathing harder and harder as she started opening *more,* feeling like Copper was falling into her, feeling like his penis was sliding deeper and deeper, as April felt herself stretched open ever further inside.

Copper’s hips sunk against her own, but before April could get her wits together, Copper was pulling *out* again. Her entire... thing around his penis was tingling, like a... tingly thing! He didn’t pull all the way out, but started pushing in again, then out, and in, and to April’s panic, he wasn’t stopping! She couldn’t make words, couldn’t move, couldn’t think about anything but her place filling up with penis, because of his sliding. If it never stopped, she’d be like this all recess! She *wanted* to be like this. She *hungered* to be like this.

Her attempts to speak gave way to a steady, urgent panting as April’s fear faded and her eyes dulled. She stared forward, as Copper’s steady rhythm seemed to let her get her wits about her again, even with the tingling growing deep inside her where his penis was pistoning. She felt like a different pony though. She’d never wanted anything more in her life than Copper’s penis inside her right now. Even if the teachers found them, she’d still keep doing it, even if other foals laughed at them. It was all April cared about anymore, turning her tail aside, locking her hind legs, and rocking back as he slid his penis in and out of her.

April’s dull-eyed calm faltered too then, because it wouldn’t stop going down. The tingling in her rear was growing and growing, as long as Copper was sliding his penis in her, and he wouldn’t stop. She felt strange. Stranger than a filly whose friend just put his penis inside her. Her gasps grew more and more frantic, rising in pitch as the tingling felt like lightning flowing through her veins, and her whole body was tensing up. She grit her teeth trying not to scream because she didn’t want the teacher to hear. What was happening to her?!

April’s body started trying to push him out, then! She felt her entire insides flex like a muscle around his penis, then relax, then flex, then relax. She tried to stop doing it, and that just made her whole situation explode, as the tingling suddenly accelerated, like it was rushing through her, like she was falling, convulsing around his penis rhythmically, not even trying to stop it. Hunching forward, unable to stop *doing* things around him in there. 

She was so glad he pushed through it, stretching her wonderfully despite the strange sensation of rippling around him in tight clenches. She wanted to cry it felt so good to be opened like that. The tingle rushed out of her slowly, leaving her dazed and panting as huskily as a filly can, somehow a filly whose best friend was mounted on her rear, and his penis was deep inside her back there.

He started swelling up like a balloon then, and she couldn’t believe it, but here she was. Standing here with Copper’s penis deep inside her, the tip expanding achingly almost all the way up to her belly button. She could’ve pointed to exactly the point along her torso where she felt him deep inside it, doing this. That was how strongly she felt it. Were they going to do this forever? He wasn’t sliding anymore, so did that mean he was done? She felt like he had something to do though. An ache inside her for something she couldn’t say.

April barely registered Copper’s penis start jerking within her before she sucked in a surprised gasp as she felt semen spurt into her. A low moan, and her convulsions returned albeit more weakly, still making her eyes roll back as the incredible sensation of his hot cum. It slid up her passage, pumping deeper even than his penis could go, then started stretching her open. 

She didn’t care anymore. She wanted to do this forever, wanted him to pump this into her forever, as her belly slightly swelled from the expanding holder of semen that was inside April. Alas, colts who are too young to do that to two or three mares can satisfy a single filly, but not make her belly so swollen with semen that she can’t even walk.

That was how April felt when, looking between her legs underneath herself, she saw her belly stop swelling as his ejaculation eased. She was standing on four sturdy pink furred legs, surrounding the four corners of a belly heavy and full with semen and penis. April loved it so much, and she didn’t even know what semen was!

She lifted her head, and looked back at him again, her orange tail flicking around behind him, as Copper sagged atop her rump, his arousal since seeing his brother do this last night at last eased. “Are you gonna...” she had to giggle drunkenly, “Pump any more of that... stuff into me?”

“I... I don’t know,” he said nervously, “So you’re okay with... I—I felt it pumping out of me. I couldn’t stop doing it!”

“You shoulda kept going until I was even fuller,” April said in teasing satisfaction, “Copper, your penis is inside me right now! You just shoved it in there! Are you okay? I couldn’t stop squeezing. That... place you’re in just started pushing you out again and again. And you just pushed in *anyway!*”

“I *loved* that,” Copper declared honestly, “You should’ve kept squeezing. That was what made me start... putting that stuff into you.”

“That was so... scary, but awesome. Where did you *learn* about this?” she asked in glowing wonder.

“I saw my brother do it,” he said with a self-conscious blush, “I didn’t know how I’d just start... pumping it into you. It just happened. I had to hold you and pull you against me and I just exploded with cum again and again, wanting to fill you up so bad. You just took all that white goo into you!”

“How do you know it’s white?” she asked in confusion.

“O-oh, well if you wanna see my cum,” Copper said, “He called it cum, by the way. But now’s when my brother pulled out. S-so look at your fillyhood, and once I pull out, my cum will start coming out of it.”

April felt a rushing sensation after the tingling sliding of Copper pulling all the way out this time, and her taut belly started to relax, as this thick white goo started swelling/sliding out of her fillyhood and hitting the ground between her legs with a splat. 

“That’s... *my* cum,” Copper said in amazement, “I can’t believe I can make cum too. That was it my body, just waiting to go into you. I can’t believe I started pumping it out of me, making it go into you. I...” He nosed at April’s inwardly purring belly, saying, “I love how it’s in you now. I want it to stay in you forever.”

“It’s not coming out as much anymore,” April said thoughtfully, “Maybe some will stay in me? I... I can’t believe how good it felt to have your cum go into me. My belly feels really good right now.”

“I’m just glad it worked,” he said in relief, “So let’s... keep as much inside you as we can. And you can have... a big belly.”

“It’s not that big,” she said disapprovingly, lifting a hind leg to look at it, “You can barely see it.”

“Well good, because we’d get in so much trouble if our parents found out,” Copper said.

Walking around, not feeling much semen trickle out of her as a consequence, April said indulgently, “Hee, my bottom place is all fulla your cum, and nopony even knows.”

“Yeah, it’s... it’s pretty incredible,” he said in bemusement.