Allie didn’t know how to get it through to him. Duster was just being obstinant about it, saying, “Come on, you don’t need to keep it secret from me. What is it you were thinking about that you like?”

Allie had been with Duster since before she could remember. Two sides of the same coin! But then her femininity had started growing achy, warm and wet that spring, and they both knew what that meant, but Allie couldn’t believe it was happening to her. She’d sit there trying to ignore it, trying to ignore that Duster couldn’t feel like this since he was a colt, and she felt like she was changing right in front of him. Like she couldn’t stop being… a girl.

They were just a couple of foals playing together, best of friends like two peas in a pod, and then Allie went and ruined it. He’d asked her what she’d been up to today, and she told him indulgently, “There were some older colts on the playing field today. I got to see them practicing, and they were really big.”

“So what?” he asked in confusion, and Allie knew she’d fucked up. Because she’d paused there to stare at the big, swarthy almost-stallions, with their tight shorts, and their big hands, and those short cut tails that colts had, and her rump really started to get hot and melty, and she wanted to just go over there and… do something with them.

“W-well it’s just… I like…” she said, trying to put to words how she had started… noticing wasn’t quite the word, but seeing colts, and thinking about what they could do to her. Male animals in general, not just the two-legged ones, that mounted their female, and pinned her down and… Allie couldn’t imagine Duster actually wanting that.

“You like what?” he asked curiously.

“I don’t want to say,” Allie said with a furious blush, shaking her head. They were playing some video games up in her very pink styled room when this conversation came up, some time before her parents got back from work. And she couldn’t tell him she had started catching herself staring at colts, because he was a colt! She didn’t want to think he thought she was staring at him! She didn’t want him to think she was a… filly, who got babies in her and got stupid about it.

“Come on,” Duster prodded her, holding his controller in one hand, “You don’t need to keep it secret from me. What is it you were thinking about that you like?”

“It’s really nothing!” she said loudly, rolling her eyes dismissively, “I’m just a… you know, a filly, and I’m just not like you.”

“I don’t care if you’re a filly. You’re awesome!” Duster replied, “You play the same games I do, you like the same stuff, we even like the same music. We’re practically twins!”

“Yeah but,” she said a little resentfully, “But it’s different. I always thought I was the same as you but now I’m… not. We just don’t think alike, okay?”

“How don’t we think alike?” he replied obstinately, “Name one thing!”

“Well… like…” she scrunched, “Like boys!”

“What about boys?” he asked.

“I like… boys, now,” she said miserably, “Not you but like… it just…”

“What do you mean ‘now?’” he asked less angrily, looking at her with concern in his baby blue eyes.

“I just think differently from you,” she said testily, turning away from his gaze, “It’s nothing you would… have to deal with,”

“Well yeah,” he said irately, “If we’re not alike, then it wouldn’t be something I have to deal with, since you’re the only one who has this secret thing.”

“It’s not a secret!” she protested, “It’s just… biology!”

“If it’s not a secret, then tell me!” he replied, “I don’t care if we’re different for some reason. I just don’t want you to feel bad about it. So how are we thinking differently?”

“I told you!” she replied angrily, “I like boys, now!”

“You didn’t like boys, before?” he asked skeptically.

“No!” she replied. Then she blushed, and turned away again, saying, “I’m… just a filly, and I’m thinking about filly things, like colts and and stuff.”

“And… you didn’t think about that stuff, before?” he asked uneasily.

“No, I’m… I’m getting older, so I’m thinking different things now,” she said uncertainly, “Things that you never think about.”

“Wait, is that why you’ve been so… weird lately?” he asked critically, “Because you just… started liking colts, out of nowhere?”

“I-it’s not like it’s unusual,” she said resentfully, folding her arms, “Every filly starts thinking like that.”

“That must be weird though,” he said cluelessly, “You just look at a colt and think… oh he looks so good?”

“No it’s more like… I dunno,” she said, sagging to gaze downward, “I can’t tell you, because you’re a colt. Y-you want to think I’m looking at you?”

Confirming her fear, he didn’t answer at first. Then he said, “It’s better than you just ignoring me and trying not to talk about it.”

She looked up at him, and Duster said so stubbornly and coltishly, “Go ahead and look at me. I’m just another colt, right?”

“N-no you’re—” she started to say.

“No it’s okay, really!” he assured her, “Just don’t worry about it. It’s normal, right? I was just curious about… what you think you can’t tell me.”

“Well I can’t,” she replied, “It’s gross, and you wouldn’t want me thinking about you like that and… stuff.”

“C’mon, I’m a colt, right?” he replied, “Don’t colts want fillies falling all over them? What, my manly figure makes you swoon~?”

He even posed for that and she had to laugh, saying, “No, you’re just an idiot! I just meant… o-other colts.”

“The older ones?” he prompted sympathetically.

“Yeah,” she said in a subdued tone.

“Well, I don’t think about colts that way,” he said, “And I uh… I haven’t really thought about fillies like… that or anything. But girls mature faster, right? It’ll probably hit me too, pretty soon.”

“Well, tell me when it does,” she says with a self-conscious chuckle, “I wanna know what it’s like when you start going ga-ga over pretty mares.”

“Well, I wanna know what it’s like, too,” he said firmly. Firmly like a big penis. She tried not to get distracted by the thought of a big, firm penis. “You don’t have to tell me, but if you want to… it totally won’t bother me at all,” he said bravely. “If it does I’ll let you know. but otherwise say whatever you want.”

“Even if it’s about m-my… private parts?” she asked him challengingly.

Another pause, and he blushed, saying nervously, “It might… hit me pretty soon I guess. You know how guys get… a boner, right?”

“Right?” she replied tilting her head at him.

“Well I started getting… boners,” he said with a full blush, not meeting her gaze, “It happens in the m-morning sometimes, and it doesn’t even feel very good. It’s just weird how my…”

“Your penis,” she prompted dazedly.

“My penis,” he said with a weak smile, “It’s just weird how it’s… getting ready to put babies into someone.”

They gazed at each other in a pregnant silence.

“So, go ahead and talk about your…” he blushed again, turning away in dissatisfaction, “Vagina or whatever. I don’t even know what you call all that… stuff down there for girls.”

“What do you call your… uhm… balls?” she asked curiously, “You know, the things that make the sperm?”

“I just call them balls,” he said with a snicker, “I think they’re supposed to be called testicles, but that sounds weird.”

Swallowing nervously, she said, “I don’t have any… balls, but the… the stuff around the opening, they say it’s called labia. Which is weird because it’s one thing, but they say like it’s two, one on each side of the… slit.”

“That’s… really cool actually,” he said, “They never even told me the word labia before.”

A pause, and she blurted out, “That is so weird to say. I have a… a-a slit.”

“Oh yeah, well I have a penis,” he shot back, growing less confident as he added, “W-which puts babies… in that slit.”

“Did you ever cum before?” she asked cautiously.

“N-no,” Duster admitted sheepishly, “But I p-probably could. Have you?”

“Well I mean… maybe a little,” she said blushingly, “S-so I can just talk about how I have a slit, and a vagina and you… like that because you’re a colt?”

“Or just because I like you,” he countered, “But yeah being a colt probably helps. So you get really… wet, huh?”

“I-I’m wet right now,” she said tensely, squeezing her thighs together, “My p-panties are all stuck to me. I just keep thinking about it, and you’re a colt and…”

“Can I see?” he asked hopefully.

“W-what?” she asked, looking at him abashedly.

“Can I see your… panties stuck to your labia and… stuff?” he said shyly, “I’ve never really seen… a girl’s stuff before. A-and you’re a girl, so…”

“You don’t wanna put a baby in me, do you?” Allie asked nervously.

He shook his head, “I’m just curious. You don’t have to.”

“D-do you have a boner right now?” Allie asked with an anxious look to his groin enigmatically concealed by shorts.

“No actually, but I… I feel like I could,” he said frankly.

Allie prevaricated. Then she imagined Duster touching her panties, her wet panties, all sticky and… and it was making her even hotter down there, to think that she could show him this. Her friend never felt this or had to deal with it, and he wasn’t grossed out and he wanted to touch them?

“J-just so you know we’re not having sex, or anything,” Allie said disaffectedly, unfastening her skirt and wiggling out of it, “But I mean, if you want to touch it, I won’t… say no.”

She looked at him apprehensively, as he looked between her legs in wonder and curiosity. “L-like what you see?” she asked nervously, spreading her legs apart.

“My… penis is moving,” he said unsurely, “Just shifting around I dunno, it’s not getting bigger. I-I’m gonna touch it.”

She tensed up as he approached, smiling nervously and saying, “G-go ahead. Wow, you’re… you’re right there. Y-yeah. Just… just grab the edge and…” she caught her breath, as Duster peeled away her panties from her moist groin. There was her slit. Her entrance. Her birth canal, right there for his penis to go into.

A frozen moment, and he said, “L-let’s get these off you the whole way. They’re all… slimy anyway.”

She felt horrible at that until he added indulgently, “Slimy with you and that’s awesome.“

He helped her get her panties off, and she breathed a sigh of relief as her fuzzy nethers could relax out of their clothing. Duster was highly interested in them, going between her legs while Allie watched with anticipation, until he touched them. Her breathing deepened as his fingers contacted her in a way that was so different from when she touched them. He dipped a finger in her, right away.

“So, this is your slit, huh?” he asked guardedly.

“Yeah, it… it feels really cool when you touch it, I don’t mind,” Allie desperately assured him.

“I guess I can see how they think there’s two of these labia… things,” he said, spreading them to either side of her entrance, stretching them. “T-that feels okay?” he asked looking at her in alarm.

“That… yeah, it… woah, yeah they really do stretch kind of weird, but I promise it’s just fine,” she assured him, “C-could you put your finger in again? That felt really… weird.”

He obliged, and actually started to penetrate her. Allie hadn’t even done that to herself! “It’s just going… into me,” she said in tense wonder, staring at his finger sliding up into her birth canal.

“I-I’m getting a boner,” he announced, “I’m really getting a boner.”

“Your penis is getting ready to cum!” she said in hunger and alarm, looking at the boy’s pants, which… looked a little bulkier, maybe? Curse his baggy shorts! “Is it making you wanna put it in me?”

“I-it smells amazing,” Duster said, continuing to stare captivated at her moist V.

“They say guys like to lick it sometimes,” she said warily, “Not that you have to but if you want.”

“O-okay, just a little,” he said, removing his finger and leaning his head between her legs. “Sorry if this’s silly,” he added, then licked her—!

Allie grunted in surprise and gasped, arching up as his warm tongue slid right along inside her slid. He pulled back, and already she was tingling. Her nipples were tingling. Was she gonna get breasts? “No that was good!” she stated to the worried colt, “Just a little surprising. N-no objections whatsoever.”

So he went back to it, and her eyes immediately sank half closed, her breathing deepening again. It was just firing those orgasmic tingles right up into her pelvis! Her legs were spread, and he was just… exploring her entrance, and even almost penetrating her, and tugging at her stretchy labia with his lips.

“I’m gonna cum,” she said huskily, hunching over Duster’s attention to her groin, “K-keep doing that. I’ll show you how I… cum. It never happened so fast before. Oh… Duster, yes, tug on…yesss…”

She tried to describe it, saying that the tingles were filling her up inside, that everything was exploding in sensitivity. She told him she had to hold onto his head, when she pulled him against her own groin, and he went into her hungry female need. A few false starts, then she told him how it caught within her, and please don’t stop, and he was tonguing at her clitoris now and she whispered shrilly, “Duster! I… I…! Ye…!”

Her whole body seized up as the climax filled her veins with pure lightning, rippling her groin into powerful clenches. “Unh, uh, unh,” she panted, rocking against Duster’s head, shoving out his tongue with contractions she could not stop. He pulled back out of her limp embrace, looking up at her but it was too late. The engine of pleasure in her pelvis would not be denied.

“I’m… orgasming… pretty… unhhh… cool… huh?” she managed to speak, hugging her nipples and writhing there before him, clenching and clenching.

Then his hand shot to her groin, and he pushed his finger in hard. If her parents had been home, they certainly would have come running up at the shriek that escaped her as he forced himself into her against her clenches, and she bucked up against his finger, declaring, “Can’t stop! Pumping my semen! Into you!”

After she’d calmed down from that killer orgasm, Allie managed to explain sheepishly, “Sorry, it’s just they say guys pump their semen into you when they orgasm. S-so that’s what it feels like to pump out the semen, I like to imagine.”

“I-it was realy cool,” he said dazedly, still eyeing her sticky groin with maybe a bit of trepidation, “I didn’t think you’d freak out like that.”

“It was the best thing I ever felt in my whole life,” she said honestly, “It was so different when you did it. You just stuck your finger in when I was…”

“Squeezing down on it,” he prompted.

“Yeah,” she said relaxing, leaving her legs splayed to show off her post-orgasmic pussy, because she loved it so much.

“That was… really incredible,” he reiterated, looking at her hopefully, “You don’t wanna see mine, do you?”

“Oh, oh I do!” she said, sitting up straight, “Maybe I can make you cum, too!”

“It looked really fun,” he said thoughtfully, “I hope I can.”

“I–I also just wanna see it,” she said with a blush, “I showed you mine.”

“No problem,” he said, wiggling off his pants and briefs. Halfway down he paused, looking at her and saying, “They weren’t stuck to anything, so I didn’t think…”

“No, it’s fine,” she said amiably. Then she realized she was looking at her friend’s half-erect penis. He pulled off his shorts all the way, and she crawled right up to it, saying, “Wow, that’s cool! You really do have a penis. I can touch it, right?”

“G-go ahead,” he said, looking at her not unlike she looked at him before he started… licking her.

She poked it, and wrapped her hand around it, declaring, “Oh, it’s so soft…” He bucked up at that, throbbing bigger against the squeezing of her hand. She found his balls below it, in a wrinkly sac that moved even as she stared at it, the orbs shifting within. “Wow, it’s just like my labia,” she said in fascination, “Y-your balls are in here?”

“Yeah, they… that’s my scrotum,” he said, leaning forward and panting at her touches and strokes. There was an undeniably attractive spicy scent down here, coming right from his penis, so Allie didn’t even need to ask. She just started licking it. Stiffer and stiffer it got, with each lick, and it only tasted a little salty, but her head was getting flooded with the scent of that dick.

He pushed her back then forcefully. She fell back with a squeak, as the colt half stood on his knees, his shaft dangling stiffly between his legs. “I wanna put it in you,” he said intensely. “It’s making me.”

Allie was so wet. “You’re a male,” she said in a voice dripping with lust, spreading her legs for him, “Come put a foal in me, you male.“

“I can’t believe I’m doing this,” he said, hungrily climbing over her to position his erection at her entrance.

“Oh, I can’t believe I am either,” she moaned, bucking up as she felt a boy’s real penis touch her labia, a penis that was going to put a baby into her. “Put it in! Put it in! Put it in!” she begged desperately as they fought together to begin having sex. Then he just started sliding up in her, deeper and deeper, deeper than she thought was possible. He vanished into her hips as she felt her vagina stretch achingly around that thick member, both groaning hard as his hips met hers.

“I—I’m in you!” he stated in amazement over her shoulder.

Hugging his chest she moaned, “You feel so good! Are you cumming in me?”

“I… I don’t know!” he said in response, “You’re so hot You’re all around me! I… I… I…”

It was hard to tell who started thrusting first. The squirming of two foals together resolved into a stronger and stronger steady, rhythmic fucking. She lay back against the bed, so she could push her hips up more effectively, wanting his penis to slide in and out so bad. Then they… messed up, and he was pushing at the same time she was pulling, so they just kind of flopped together.

Stopping, Allie declared urgently, “Okay you pull out, and then when you push in I’ll push back so we’re always sliding in and out.”

“Am… am I gonna put a baby in you??” Duster asked, penis pressed against her cervix, hips held heavily against hers.

“I can feel where you’re gonna do it,” she said in awe, laying a hand on her belly. Duster sat up, putting his own hand on her belly, feeling where his penis was underneath… inside her.

“I… I wanna do it,” Duster said lowly, grabbing her hips and pulling out again.

“Okay you—hahh~!” she tried to coordinate as he shoved in her again. She bucked up—no! He pulled out and she… and… and then she got it, bucking up right when he pushed in, and both pulling back together. It was like a switch had flipped in her brain. In out in out in out, she had to keep that amazing synergistic pistoning, as he hugged himself to her and pressed her down, and she hugged her legs to him, and arched up to consume him into her body.

He pulled back at last as if oversensitized, and something expanded within her as his thrusts turned short and deep. “It’s… filling me up! Just like you said!” he declared urgently, “Am I really gonna… put a baby in you?!”

She didn’t know how to answer, just thrust, thrust, thrust, and of course he was going to put a baby in her. She needed it.

“Allie I… I think about fillies… with big bellies!” Duster confessed anxiously, grinding against her as it filled him up with the need to ejaculate, “About… babies… pushing out their vaginas! I want you to… between your legs… I’m gonna make you…”

“We’ll be secret somewhere, we’ll…” she said deliriously, as he pushed hard against her and that secret place within her filled with his need, “I’ll push the baby out right in front of you.” His whole body was stiffening against her as she whispered, “I’ll foal… in front of you. You can even lick me and I’ll… foal while you lick me, and… oh,” his penis rhythmically kicked in her, and something hot and wet started pumping into her. wow….

“That’s it,” she murmured to the trembling boy above her as Duster heartily ejaculated into her womb, “Pump it all into me… y-you look good. I’ll have your baby now.”

He relaxed as the semen spurts ended, and the two panted there, covered in sweat, the one staring into the other’s eyes, no need to stare at their groins any longer, because they knew exactly what was going on there.

“What’re we gonna name… the foal?” Duster asked in cautious dread.

“I dunno, I just wanna… give birth to it,” Allie said frankly, “And I never told anypony I wanna… give birth with my vagina. Like really squeeze it out of me.”

“I-it might not have worked,” Duster said, looking at their groins despite his confidence that his seed was within her.

“We’ll just have to do it again and again until it does,” Allie said giddily. “I don’t have to… touch myself anymore. I can just let you… cum in me.”

“You’re… you’re welcome, I guess,” Duster said nervously, “I can’t… what am I supposed to do now? All the… feeling stopped.”

“Just pull out I guess,” she said thoughtfully. As her gaze drifted to the distance at the feel of his softening shaft dragging out of her, he asked,

“You really felt that, huh.”

“I’m a… I’m a filly,” she stated somewhere between feeling self-conscious and lust drunk. Sinking a finger into her impregnated pussy before him, she declared, “I’m a female. I wanna stare at colts, and I want them to do this to me. I wanna feel their penises inside me. And I wanna get a big foal in my belly, and push it out of my vagina. I-it just started happening to me. I just started thinking about it, and I’m gonna do it now. I’m pregnant maybe. And I wanna be pregnant. And… that’s why we think differently now.”

Shrinking before him a bit, Allie said unhappily, “I wanna be a girl, and a pregnant girl, and a mommy I guess. A-and I can’t stop wanting that stuff. I can’t think like you, because I don’t have a penis, a-and my vagina just wants it so much.”

Scrunching his muzzle in disagreement, Duster said, “Well, I want you to have all that stuff too, so maybe we’re not thinking so differently after all.”

The second time, and most often after that he just pushed her down on the bed and started fucking her right away. He gave little indulgent grunts as he ejaculated, and she gave little indulgent grunts as she filled up with his babies. And then they’d separate and just play together, do something more if the mood struck them. Allie found Duster really liked to lick her and only got impatient about it if he hadn’t impregnated her yet. So she made sure to get him to impregnate her, and told him his semen was turning her pregnant while he buried his snout between her legs. So she always tried to be ready to get him pumping his semen into her vagina right away, so that they could relax and take it easy afterwards. “Your semen’s doing work on me in there,” she’d tell him slyly, hand laid across her belly. And he’d go straight for licking her then, sometimes before she even got out of the chair.

She did hide it from her parents, and she did start putting on some weight, but her parents just thought she was having a growth spurt. “You’re having a growth spurt in here,” Duster joked lovingly, putting a hand on her belly that’d just started to swell.

At one point, she gasped out, “What about the… the foal can you just…” and his response was,

“Our foal better get used to getting covered in semen, ‘cause I’m gonna keep doing it to you.”

“Duster, I love you so much. ♥“ she said in aching pleasure, as she felt Duster’s penis start pumping cum up into her belly right where her foal was. She pushed hard against him after that, to make sure her foal got covered in cum, feeling that semen pumping into her, growling, “Yeah… fill’m all over in there…” She didn’t know why she loved it so much, but the foal didn’t stop growing so Allie figured it was harmless enough. And Duster’s semen increased with repetition, so sometimes she’d pat her pregnant belly afterwards, murmuring to him, “I think there’s more seed in here than foal.”

That soon became an impossibility, as quite a while later, an older and heavily pregnant Allie moaned, “Oh gosh, the foal’s… pushing it out!” as Dusty pressed his belly against her gravid womb, his more mature penis trying to fill her, even as his cum splurted out between her legs and squelched messily between them. She rubbed her taut belly, trying to get more semen in there, trying to show her foal how wonderful semen was, and she felt his insistent penis spurt in there at last, falling into an orgasm as she imagined her child giving birth so hard just like she wanted to do.

“Thanks, I…” she said breathlessly, as her own orgasm wound down, still dripping between her legs with cum, “I needed that,” she said at the same time as Duster.

“Told you we think alike,” he added with a wink.

“Say that to me again when I’m in labor,” she remarked in a very unimpressed tone.

And… she may have screamed louder than him, but it was nice to have a colt around who knew how you thought, when you were too busy giving birth to think. A different colt would have ceased his attentions when she screamed, “Licking me?! It hurts! It hurts! Ahh it—ahhhg! You bastard! Stop! The foal is—! Ahh! Help me you—idiot! I can’t stop! Pushing—help—I–I can’t…ahhggghh!” but somehow impossibly, it was the most wonderful and amazing thing he could have done for her. She couldn’t stop hating him, and the pain, and everything, and she loved it so much she wished she could stop this burning, passionate rage long enough to tearfully thank him. She’d remember the feeling of his tongue along her straining, crowning labia with an aching fondness for years afterwards.