Sex Ed 101

She certainly was in this case.

I went to the student health center for the first time ever. I walked right by the pharmacy with a sinking recollection of Katie's request that I had never obeyed, and I went up to the nurse. One test later, and it was confirmed.

My twin brother had knocked me up.

--

Jason took it well, all things considering. He stared at me for what felt like minutes on end and mutely put both hands onto my lower stomach. He breathed deeply.

"Are you okay?" he managed.

"I think so," I admitted. Maybe I shouldn't have been okay. But I really was. I had wanted my first experiences to be special, and what was more special than having the guy you know best make a baby inside of you?

"Okay. If you're okay, then I'm okay."

I laughed a little at that. "Of course. We're twins, after all."

--

My belly grew quickly. Too quickly. I went back to student health for my first scan and promptly found out that I had two babies growing in me.

"Twins?" I gasped.

"Looks like it," the doctor confirmed. "Twins can run in families, so it's not entirely surprising." The doctor looked at me, and then at Jason.

I had brought Jason with me, having quietly told the doctor that I wasn't sure who the father was and wanted my brother with me during this tough time. The doctor had easily agreed.

I turned to look up at Jason now, only to see him already staring down at me. His eyes were wet with tears.

As soon as we left the doctor, his hands were on my stomach, cradling its impressive curve.

"I can't believe it. We did this."

"You did this," I corrected, but I was grinning. "You and that fat cock of yours.'

He had the decency to blush. "I really am sorry I came in you."

"I told you, it's alright. It's kind of flattering, actually, that you were so turned on you came after about one second inside me."

He breathed out a quiet laugh. "You're really okay with all this?"

"I am."

He nodded, and then repeated: "We did this. You and me. We made two little people, just like mom and dad made us."

The thought wasn't just hot -- it was overwhelmingly so. The idea that we had been formed in a womb together, grown together, and that he had placed himself deep inside me to continue the cycle was the most beautiful thing I could imagine.

--

It was about three months into my pregnancy that Katie sat me down.

"I have an idea," she said. I was a little nervous, since the last time she said that I ended up super knocked up, but it's not like there were any more potential pregnancies involved.

"Let's hear it."

She proceeded to explain that -- technically speaking -- I hadn't really fucked either guy.

See, in Katie's mind, sex with a condom wasn't real. She said she wasn't planning on telling me that ever, since it was just her opinion, but now it felt relevant. So that's why I hadn't fucked Seth.

And then Jason was obvious: he had stuffed that huge pole in me and cum immediately. That didn't really count. Even I could agree with that.

Because I was already massively pregnant, this was the perfect opportunity, Katie reasoned. Essentially, it was time for Sex Ed 102.

There was one other pertinent piece of information here: pregnancy had made me incredibly, insatiably horny. And masturbating really wasn't doing it for me anymore.

So I said yes.

Katie clapped. "Good!"

She stood up, and I watched in confusion as she walked over to the door. Was she leaving?

She pulled it open, and Seth and Jason were standing right there.

"We figured you'd say yes," Seth said.

They were both in coats -- required to go outside, but unzipped now-- but even the layers couldn't hide the way their bulges strained against their pants.

Unconsciously, I licked my lips. And much more consciously, I nodded slowly and dragged my eyes up to Jason's.

"What are you waiting for?"

--

I decided I liked being pregnant.

And why wouldn't I?

My stomach continued to grow. I bought plenty of maternity clothes, of course, but I secretly loved wearing my old shirts. They didn't fit, of course: the fabric was stretched taut, many riding high enough to show my popped belly button. I loved wearing one under an unassuming coat, sitting in the front of a lecture hall, slowly unzipping, and watching as every man did a double take.

I felt absolutely gigantic, but I loved every second of it, especially once we found out we were having one boy and one girl.

Every inch I grew was a reminder of how big Jason's cock had felt in me and how I had known that his huge cock head was keeping every drop of cum in me to knock me up right then and there.

Every kick was a question: is that mini-Jason, or mini-Jill? I hope they're getting along in there, because we're going to want them to get along really well once they're grown up out here.

My tits grew too, big enough that they fit perfectly in the palm of Jason's hand. Once again: like our bodies were made for each other.

That was all nice, but what was really great was the sex. I got fucked at least once a day, sometimes once by each of them.

Seth liked taking me on all fours with his long cock shoved inside of me, and with each stroke his balls would hit my clit.

Katie would lay beneath me, kissing me and rubbing my belly as it hung down.

Sometimes he'd cum inside me -- it wasn't like he could get me pregnant, after all -- and shoot rope after rope right into my cervix. And every time, the heat of his cum made me follow quickly after.

And then sometimes he'd pull out and aim between us. He'd splash his cum wildly, on my belly and across Katie, and she'd rub it onto both of us.

Rarely, he'd pull out of me at the last second and stick his full length right up into Katie. It always made her shriek -- she was wet and ready from watching, but he was still so big -- and he'd start cumming immediately.

She had an IUD, but that didn't stop them from pretending: "it's all going inside me," she'd say. "You make so much cum in those big balls and you saved it all for your sister."

"Just for you, baby," he'd respond. "I'm pumping you full. I want to knock you up just like Jill. I'm going to make your tummy so big, sis."

She'd groan and whimper, and I'd wish I could tip my head down to see Seth pushing his seed into his twin again and again, but my belly was too big. Their talking was usually enough, though.

"Stay inside me," Katie begged. "If you pull out the cum will drip out and I won't get knocked up. I need you to knock me up, Seth. I need your baby inside me."

Like I said, it happened rarely. But that was my favorite every time.

So I always enjoyed a nice fuck from Seth. But Jason, oh--

Most of the time Jason liked me on top. That meant he could put both of his hands on my stomach, and he always liked to comment that it felt a little bigger than the last time.

This also meant I could ride him slowly, sinking down onto him inch by inch. He still felt massive inside me, like a baseball bat splitting me open.

("Better get used to that," he joked once. "I think our babies heads are going to be a bit bigger than me." Honestly, I wasn't sure.)

"You feel so good," he'd say. "You take me so well."

"Jesus, if you told me growing up that my brother's cock is as thick as a Coke can, I don't even know what I would've done."

He laughed at that.

I'd grind against him until I came, and then he'd take over and thrust up into me until he followed shortly after.

But then sometimes, he'd lay behind me and cradle me, hold me close and caress my breasts and belly and whisper how beautiful I was into my ears.

We did this more and more as I continued to grow, since riding him got a lot harder with my belly so big.

We did it the night I went into labor, in fact. I sort of think he made my water break by shoving that thing inside me, but I'll never know for sure.

--

I went to the pharmacy a few weeks after I had the twins, and I got on birth control. Finally, right?

It was an easy choice: I wasn't going to stop having sex now, but I needed to at least graduate college before I even thought about getting knocked up again.

I kept fucking Seth, and Katie kept occasionally fucking Jason. But it happened less and less frequently individually, until it only happened when we got together for a foursome. Then we'd swap. But our brothers became our de facto partners.

--

Years passed. Jason and I moved far away from home, of course -- you can't exactly raise your kids together in a town where everyone knows you're siblings.

We kept in contact with Katie and Seth, visiting each other whenever schedules aligned.

One year, we arrived to a surprise: an IUD packaged in a neat little box.

Jason clearly didn't understand: "Katie, you're great, but I already always fuck you with a condom."

"I know, stupid. That's not the point."

He just stared: some things -- including our shared innocence and occasional stupidity -- never change.

"I got it removed for a reason," she patiently explained. "And I figured you two would want to watch the special moment."

So that's how we found ourselves living out that fateful college moment, but this time in reverse. They had us start first, had Jason work his way up inside me while I gasped and held his shoulders and Katie and Seth watched.

Katie, ever the bold one, muttered an uncharacteristically quiet request: "Talk to him? About... you know."

So I did: "Are you going to knock me up again, Jason? You did it by accident back in college, just stuck your cock inside me and put two babies in me. If you do it on purpose, I bet you can do better than that."

It was only when they were utterly and totally worked up, impulsively rocking against each other, that Seth slipped inside Katie. I knew his cock well, but I knew I'd never experience it like she did.

That was a feeling reserved only for his twin, the one person in the world made to fit him exactly.

I really believe it's the most special moment ever, having that psychic twin connection that makes you understand precisely what you both need as you get filled up over and over by the boy that was raised with you.

It only took a few strokes for Seth to groan and freeze, and Jason and I watched eagerly, knowing we were watching another pair of twins make a new life.

I'm not sure how we all knew it was happening in that moment, but we did. Seth pushed up as hard as he could and groaned, as it he were trying to thrust his way straight up into her womb. Given how long he was, he probably got close. And Katie shoved down just as hard. As Seth's balls pulsed and pulsed and slowed, we knew -- all of us -- that Katie had just been bred.

It was such an incredible sight that I didn't even realize that Jason was pumping his own cum inside me at that very moment until after.

A few weeks later, we got the joyful call from Katie. She was only pregnant with one, so she assured me that they'd be having another someday. A pair is best, she said with a laugh.

--

As for Jason and I, we were happy with our two. The twins -- Maddie and Nathan, because we couldn't bear to continue the alliteration thing -- grew up.

Nathan looked like me, with light brown hair that tended to flop over his big eyes. His penchant for soccer kept him strong and lean.

Our daughter took after Jason: blonde, wavy hair, and a naturally lithe frame. But he was tall, and Maddie was not: she was decidedly below average height, a born ballet dancer.

And yes, we decided to home school them.

If I do say so myself, we did a pretty good job. Like I said, our family had never been weird shut-ins or anything. The only issue Jason and I faced was our lack of options for experimentation.

But there was an easy solution to that, we knew. So on the twins' eighteenth birthday, we introduced a new course to their home schooling curriculum. Sex Ed 101, we called it.

They were unsure at first, just like we had been, so we followed the same steps Katie had until they were comfortable.

When they were ready, their first times were with Jason and I -- protected by condoms, of course.

Maddie struggled with Jason's cock, as I expected she would. We had him lay down and Maddie straddle him, so she could take him at her own pace.

I sat next to her, and she held my hands, gritting her teeth as she tried in vain to sink down onto her daddy's length. That first time, she only managed to get a few inches in her, but I was so proud that I licked her to three orgasms that night. And then the next time, she took almost the whole thing.

Nathan wasn't as thick as his dad, but he had an extra half inch or so to work with. He slid into me hard and quick, and I came on the second stroke as he hit me in just the right spot again and again. He had stamina, too, fucking me for almost a half hour before he stilled and I felt him pulse inside me and release spurt after spurt of hot cum. I knew he'd be perfect for his sister.

We changed the lesson plan for the final exam. After all, Katie had never intended for Jason and I to really fuck. But Maddie and Nathan were ready and wanting.

I knew Maddie was unprotected, but I wanted -- needed -- her to experience the beauty of that first unprotected moment, and she agreed wholeheartedly. I booked her the earliest appointment I could for a few weeks later, to get her on birth control.

And on that final night of lessons, Jason and I brought our twins into our bedroom and prepared them. We laid Nathan down on the bed, and I sucked him until his dick stood proudly upward and his breath came in heavy pants.

We sat next to him and helped Maddie straddle her brother.

Jason stroked Maddie's hair, telling her how proud he was of his little girl, as she sank down onto Nathan with a squeak. As soon as he was fully in her, they both froze in unison.

Like children, like parents.

I'll never forget that first moment when Jason was fully inside me for the first time and I understood at last what it meant to be a twin. And I knew now that neither of my kids would ever forget either.

Maddie looked over at me in awe. "Mommy, he fits inside me so good."

"I know," I said, and I did. I knew better than anyone. "You're twins. It's what you're supposed to do."

"Yeah," she whispered.

Nathan murmured his agreement too. "She's so tight, oh fuck."

I felt the bed shift, and Jason moved behind me. He pushed into me as Nathan began to thrust up into Maddie, and I felt like I was crumbling. From the inside out I fell apart, each and every nerve in my body going haywire and then numb, and my limbs turned weak. I tumbled forward, catching myself on Maddie's shoulders as she giggled.

"I guess daddy's cock is big for you too?" she said.

"Every time, sweetie. Every time."

Our hands on each other's shoulders, my daughter and I balanced each other as we got fucked deeply, fully. She made the cutest noises, little gasps each time Nathan bottomed out in her and disappointed sighs each time he withdrew.

"I'm getting close," Nathan gasped out. "I'm gonna--"

He dug his hands into Maddie's hips and pulled her down. Maddie had no intention of going anywhere, but I helped too: I pushed her shoulders, sinking her down, making sure her brother's cock was as far in as it could go. His whole body jerked as he came, and she let out a long cry.

They stayed like that for a while, panting wildly and trembling through the aftershocks of their orgasms, and then she leaned down to curl into him.

"I feel really warm and sticky," Maddie laughed. She squirmed a bit as she pulled off of Nathan and looked down to watch his cum stream out.

"That's neat," Nathan said. "It's crazy that it all fit inside you."

"No wonder it felt like you were blowing me up like a balloon!"

Nathan shrugged, seemingly almost embarrassed.

"Your brother will probably always cum a lot, just like I do," Jason explained. Maddie nodded.

And as if to prove his point, Jason thrust once more within me and came, but his thickness plugged all of his semen inside of me as he pulsed again and again. He stayed in me for a long moment, rubbing my back gently.

I had never felt so complete.

Finally he withdrew and slowly clambered back next to me on the bed.

Soon we were asleep together, the four of us spread eagled across the bed.

--

We didn't end up going to that appointment. It was already too late.

But I did have to take Maddie to the doctor soon anyway.

This time, I was the one sitting next to the examination chair, as my daughter watched the doctor press the ultrasound machine to her stomach.

And that's when we found out that twins really can run in families.