Sex Ed 101

Katie, on the other hand, wasn't silent. "Oh fuck! I can feel it all! Fuck, you're cumming so much. You better not break that condom with all your cum. I bet you'd get me so pregnant. I bet you'd send all that sperm right into my womb."

Our orgasms fading, we fell against our partners. Slowly, the guys withdrew and carefully tossed their sagging condoms. And then we all fell asleep.

--

Katie was waiting for me when I got back from class the next day, just as I expected.

"So?"

I didn't even know where to start, so I shrugged aimlessly and happily. I couldn't stop smiling.

"Good right?" she asked.

"So good."

"What was the best part?"

"I-- don't know."

But I did: the best part was that moment of eye contact with Jason, knowing that he would do anything for me and I for him. I couldn't tell Katie that, though.

"I think it was the moment both guys got fully in us," I said. A close second to the real answer, to be fair.

Clearly it was the right thing to say, because Katie nodded vigorously.

"I can't believe we both have brothers with such massive dicks. Like, what are the odds? You were a champ, for real."

"I'm still a little sore, to be honest."

"Do you think I'm not? You saw Jason's cock. That thing should be labeled heavy machinery!"

We laughed together, and then I paused, earnest. "Katie, uh... thank you. I mean, for the lessons. I think they were helpful."

She wrapped her arm around my shoulder. "Jilly bean, it's my pleasure. But we're not done yet, remember."

I couldn't imagine what we still had left to go.

--

It was almost a month before the grand finale. School, then a particularly bad period on my part, then a bout of the flu on Seth's had all gotten in the way.

I wasn't even expecting it when it did happen. I wish I could say I had forgotten, but I was tantalized by the thought of what this last lesson might be.

For that whole month, I found myself reliving our group fuck during every moment I had alone.

I would start off thinking about Seth. Obviously. The way he sunk into me, the way he touched a depth within me that I didn't know existed, the way his whole dick pulsed as he came.

But every time without fail, when I closed my eyes, I remembered the way Katie's folds looked stretched around Jason's cock. The way she bore down to fit more of him inside. I imagined what that would feel like, and I came.

Every other lesson had taken place at night, when the sun had set and it was easy to blame our actions on the hour.

I woke up to Katie dressed in the room one Sunday morning and bouncing with nervous energy, and I knew this final lesson would break the mold. The boys arrived minutes later, with me still barely out of bed.

"You couldn't have let me get ready?" I grumbled.

"Doesn't matter, because you're getting naked," Katie said.

"What?"

"You too, Jason," she added.

We both stared: where was she going with this?

"Come on now."

So we did. We stripped, and Katie and Seth stood across the room from us fully clothed.

"What now?" Jason said nervously.

"Now we touch you."

They approached us, but their touches were light, unsatisfying. Seth stroked my breasts gently, barely brushed over my nipples. He stroked one finger over my folds but not in them until I groaned and begged: "come on, Seth, what are you doing?" But even then he didn't put even a single finger inside me. He swiped around my clit, so close to what I needed.

Jason seemed similarly frustrated: Katie was paying more attention to his thighs than his cock, rubbing her hands everywhere except where he wanted them most. Every few seconds, she'd ghost a finger along his length or across his tip, and then she'd retreat.

I was quickly growing frantic. Was this their grand finale? Torture?

"Do you think they're ready?" Katie asked.

"For what?" Jason said, but she ignored him.

Seth nodded. "I think they're ready."

They stepped back, and I held back a groan.

Katie grinned that devilish grin that got us into this whole mess. "Now you're going to watch."

I'm not sure I've ever seen someone move so fast as Katie did when she pounced on Seth. They stumbled back to her bed, landing with him above her.

Jason was stroking his own cock at the sight. It wasn't a bad idea, self satisfaction, but I had to know where they were going with this.

"What are you two doing?" I all but yelled. "And what are we supposed to do?"

At that, Seth looked up. "You two can do whatever you want. Only rule is that you've got to stay naked."

I looked at Jason. I wanted Jason.

"We've already made out once," I offered. Like it was at all the same.

But he went along with it. Maybe he wanted me too. "Yeah. And we've seen each other naked. Combining those things isn't too bad, right?"

"Right." In that moment, I really believed that. We'd stick to making out and watching, get off, and that would be that. We'd have done the final lesson, the last big test of our wills.

"Uh, okay then."

Jason sat on the edge of his bed, uncertain. He looked nervous, somehow small, despite the very, very big pole sticking out from between his legs.

I knew I needed to help him. As a sister. As a twin. We had made it this far together, but we were both unsure of this final leap, whatever it might be. One of us had to be brave, so it was going to be me.

I pushed his shoulders until his back was against the headboard, and I climbed over him.

"See?" I said. "We got this."

For a moment, I turned to watch Seth. He had reached out to cup Katie's tits in his hands through her shirt, and they seemed to overflow from his grasp.

He was rutting into her now, hard. He'd piston his hips down and she'd grind hers up, and they'd meet with just a few layers between them. Each time they separated, I could see the dramatic bulge in his shorts, big enough to make the fabric of the legs shift up a bit on his thighs to accommodate it.

Then Jason grabbed my chin with one hand and tugged, and my gaze fell back to his. Without breaking eye contact, he slid his free hand up my stomach and palmed my breast, and I groaned unwittingly. His hand was so warm, fingertips burning prints into me that sent heat straight down to my center. The sound clearly encouraged him: he immediately pinched my nipple and leaned up to kiss me intently.

I had been hovering over Jason, but supporting my weight quickly became too much, and I collapsed down onto his thighs. The mere inch of space between us hadn't been a lot to begin with, but it had been enough: I wasn't aware of just how hard he had gotten. And then suddenly I was extremely aware, as my clit landed against what felt like a steel rod.

We were naked: Seth & Katie had told us to be, after all. Thankfully, Jason's cock had its ever-present curve, and it was stuck up against his belly versus out where my pussy had just fallen.

I had known he was thick after watching him stretch Katie's pussy open, but I hadn't realized how thick until now. His length forced my folds apart and rested right in between them. I felt his cock throb.

We both froze. Jason jerked back slightly, panting. The movement made me slide against him. I was so wet, and he felt so hot against me. I couldn't help it: I pressed down just a bit. It only made the ache worse.

Our eyes -- both that same shade of blue -- met, wide.

"Jason, I--"

He spoke at the same time: "oh shit, I'm so close already--"

And then: "oh fuck." It was a male voice, and for a moment, I thought it was Jason's again. In my frenzy over my brother's cock, I had forgotten that there were other people in the room.

But then a feminine "my brother feels so good" followed, and Jason and I both spun our heads over to the other bed.

I'll tell you what I expected: Seth with his hand down Katie's jeans, pushing his thick fingers into her. He'd put his weight into it, hitting that perfect spot over and over because they were twins and he just knew her body like that. And she'd wrap an arm around his shoulders to hold him close as she writhed and writhed and finally came.

I imagined maybe she'd have a hand palming his shorts too, rubbing his length over and over, returning the favor as best she could as sensation overwhelmed her.

And I figured if I got really lucky, he would have taken off her shirt so I could see her tits bounce as she moved. I mean, that's the obvious thing to do with his other hand. That's what I would do if I were him. He'd pull and knead her breast, flick her nipple until it stood firm and sensitive.

That's not what I saw when I turned my head, though.

Well, I first noticed that I was right about her tits: her shirt was pulled just over them, forcing them together a bit and making their bounce seem that much bigger.

But then I noticed the rest: Seth had every single inch of his cock stuffed up inside his twin sister Katie.

He pulled it out slowly, and I stared as each inch slipped free, glistening with her wetness. It looked like they were screwing gently for those first few moments, until he got out to just the tip and slammed it back into her.

Her head flew back against the pillow, and she gasped again: "oh, so big so big so big."

But she was taking it all. I could see Seth's hand between her thighs, rubbing her clit, and a few inches above that, I swear I could see her stomach bulge a bit with each thrust. He was that deep inside her.

I heard Jason mumble "are they--" in a sort of dazed voice. But I was so intensely focused on what I was watching that I barely processed his words, and I certainly couldn't bring myself to respond.

Katie was holding on for dear life, both arms wrapped around Seth's back, nails clawing into him. I was sure he'd have scrapes everywhere later, but he didn't seem to mind. If anything, it encouraged him, and he pounded into her again and again.

"Harder, baby, harder," she began to chant. So Seth gave her a particularly hard thrust that made the headboard slap loudly into the wall behind it, and Jason and I both seemed to break out of our trances at once.

That would've been great, had we not seemingly decided on opposite courses of action. See, I decided to lean back, but he decided lean forward. And because I had been balancing most of my weight on my hands on his chest, that didn't really work out.

His movement made his dick jut out, no longer firm against his abs. And I successfully leaned back for a moment before losing my balance and falling back against him. Only this time, the tip of his cock -- oh-so-thick and dripping with pre-cum -- was exactly in the right position.

And that's when it happened.

I knew Seth had told Jason that holding off on cumming for a few days was a great way to massively increase the size of his load and that Jason had taken to doing that occasionally. I also knew that he came a lot to begin with.

I knew that my period had ended two weeks and one day ago, and I knew I had woken that morning to that sharp pain in my lower abdomen. I had seen a doctor for that once during my early teen years; since then, I knew to expect the ovulation pain monthly.

So I landed back on Jason, and Jason reared up into me, and suddenly about three inches of his thick cock were up inside me.

I had never been stretched even close to that far. He felt like a fist reaching up inside of me, pushing me wide open. I shrieked and leaned forward, but all the motion did was drive the rest inside me. I looked down: my folds were stretched obscenely, and all I could see was the very base of him, where his cock ended and balls began.

My brother's dick was in me. Oh fuck, oh fuck.

My hands, still on his chest, rose to his shoulders and gripped hard. I looked up at Jason in shock, about to pull myself off of him and apologize frantically.

Jason had been close before -- he had said as much. Even just the mere slide of me against his length had left him trembling. Apparently watching Seth and Katie rut had put him even closer to the edge.

Because just as I looked up at him in horror, his eyes slid shut and he groaned a quiet, "oh, Jill."

I thought his dick had been hot, like burning flesh against me and then inside me. I was wrong. He pushed up further -- not that there was anything more to shove inside me -- and sighed as he came, and I then understood what true heat felt like.

His cock gushed inside me, throbbing once, twice, again. It kept going, and each pulse pushed a wave of hot cum against my walls. I had been right: his girth was so wide that little cum could escape. A few drops squeezed past him and out, dripping down around my thighs, but he kept cumming, and I felt it all in me, trapped and beating up against my cervix.

My body was overwhelmed. I had orgasmed many times before, but this was a whole different level. Somehow in that moment, I knew that my twin brother was creating new life inside of me. Somehow I knew that those sperm shooting up into me were sneaking through and racing toward the egg that awaited them. It was too much. So instead of pulling myself off like I had intended, I came harder than I had ever cum in my life and let my whole weight drop against him.

Distantly, I heard Katie gasp. "Oh shit, Seth, look. They're fucking."

Seth must've turned his head, because he let out a low, deep moan. The steady beat of his thrusts didn't stop, though, and a moment later he choked out: "Fuck, I can't hold it back, I'm cumming!"

I knew what that felt like after our last lesson: Seth's cock had felt like it was up in my guts, probing deep inside me in a way that made my body's natural urge to procreate run wild. 'Fill me,' my body had seemed to scream. 'If you come this deep, you'll seed me so good.' But Jason's cock felt like it was made for my pussy alone, like it fit perfectly, exactly.

It made that urge become a real possibility, and then a reality.

There was one more thrust, and then silence as Seth filled Katie up. I knew what that felt like too, even though we had used a condom: Seth's cock grew thicker, and he pushed every millimeter inside you as he came.

A condom. Fuck.

I quickly lifted myself onto my knees and let Jason's softening length slip from me. A torrent of cum followed, more than I had ever imagined could fit inside me. It dripped and puddled around the base of his cock.

He looked dazed and somewhat braindead, eyes wide and glazed, oblivious to my panic.

Seth and Katie were oblivious too. He nuzzled into her shoulder as she cooed at him: "thank you, baby. That was so good."

He slipped from her, and a trail of cum followed. A stream, compared to my dam, but my thought in the moment was that at least they hadn't used a condom either.

I turned back to Jason. "You came in me?!"

That made him awaken. "I-- Fuck! Fuck. I didn't mean to. I'm so sorry, I--" He shook his head, not knowing what else to say.

No part of me remembered the pharmacy conversation from months ago. No part of me considered birth control at all, ever, during any of this, which meant I certainly didn't assume that Katie was on it. But of course, she was.

Katie, however, did remember the pharmacy conversation. In particular, she remembered my agreement. She assumed I had gone. She assumed I was protected.

So she laughed, a light giggle that only comes after a great orgasm. "Oh Jilly bean! You officially get an A+ in sex ed."

I was so overwhelmed, distracted by the continued drip of cum from between my legs (how was there still more?), so I stuttered out a "Huh?"

"We never thought you two would fuck! We just wanted to watch you dry hump a bit. That was going to be the big finale: some brother-sister rubbing action. But you two went above and beyond, and you get major extra credit for that."

Seth was watching us with a grin on his face, clearly equally unperturbed. And Jason, despite his panic mirroring mine, was gently palming my ass.

My realization had somewhat thwarted my post-orgasmic bliss, but I had to admit I still felt pretty great. Each drip of cum made a shiver run up my spine, and I couldn't tear my eyes away from the similar state of Katie's pussy.

Plus, well, Katie and Seth had fucked too -- and clearly not for the first time!

So I made what would end up being my final and biggest decision: I decided it wasn't a big deal.

After all, who gets pregnant after precisely one thrust of unprotected sex?

I leaned down into Jason, resting my weight on his chest. He wrapped his arms around me.

"Proud of you," Katie said, and I raised my head just enough to see her wink.

--

The lessons stopped after that. Katie hadn't lied: we had passed with flying colors.

I went from a crazed, sex lesson fiend to, well, Jill. And Jill was still as awkward as she had ever been, so I definitely wasn't getting laid on the regular.

The semester was coming to an end, and I had an exam in nearly every class. So when my period didn't come, I didn't even notice it. I would have thought it was stress related if I had.

We went home for the holidays, but I spent Christmas Eve with some sort of stomach bug, puking up the whole wonderful meal my parents had cooked. I remained nauseous through New Years, and I decided not to drink in case it set my stomach off again.

My parents urged me to see a doctor, but I was sure it was food poisoning and brushed them off. I blamed it on our neighbor: she was getting pretty old, and I was sure I had seen some under-cooked chicken in the pot pie she had brought over.

I wondered constantly if Jason and I were ever going to acknowledge what happened. But he didn't seem to want to, and I wasn't sure how to bring it up.

Mostly I wasn't sure what I wanted, honestly.

I didn't particularly want to just say "hey, remember that time you stuck your cock up in me? That was weird!" since that felt obvious.

So it seemed like I should only bring it up if I wanted to do it again. And did I?

The obvious answer was yes, but I wasn't sure if that was Jason-specific or just my newfound desperate need for dick. I had gone from zero to one hundred pretty quickly, and the descent back to zero had been equally as abrupt.

At night, I was willing to admit I wanted Jason. I'd push my hand between my thighs and slip two fingers into myself. Previously, that would've been enough, after curling them just right. But then it stopped being enough, and I had to put a third finger in, feel myself stretch like I had when my brother was throbbing inside me.

Every time I did that, I would cum immediately, shaking as I stretched myself open again and again.

But in the daytime, that was harder to acknowledge. I knew I wanted to fuck, but I couldn't admit I wanted Jason, only Jason, my twin brother Jason.

--

By the time our break was ending, I had gained enough weight that some of my sweaters rode up at the bottom, showing a little of my midriff over the rise of my jeans. I thought it was weird, given how little I had been eating. But Christmas is Christmas, and I figured there had been plenty of sweets around during my periods of health.

And Katie had told me that the cropped look was in, so maybe I'd be stylish for once. I was a little excited at the thought.

Soon enough, spring semester was beginning. I got back first, and I had unpacked and rested for a day when Katie returned.

I was on the bed in pajamas -- a tank top and shorts -- when she walked in, dressed for the trip in long pants and a coat.

She stared. "Jill, what the fuck?"

Confused, I stared back. I assumed she was talking about the difference in our outfits.

"I got back yesterday," I explained. "So I'm already unpacked."

She didn't appear to register my words at all, didn't even blink. Just stared. And then: "When the fuck were you going to tell me you were pregnant?"

--

If I had learned one thing over my first few months of college, it was that Katie was usually right.