Biology and Babymaking

My cock swelled and pulsed as I plunged deep inside her one last time, and a massive spurt of cum shot out of my cock, visible on the camera for all to see. A second, third, fourth, and fifth as well, my sperm flooding her pussy and on their way to Sara's waiting egg.

My orgasm subsided and I held myself inside her as Makenzie brought Sara to her second orgasm in the last 20 minutes, the walls of her pussy pulsing around my cock. Seeing it on camera was incredibly fascinating and erotic.

Finally, it was over. I rolled off Sara, who was instructed to lay on her back. Makenzie placed a foam pillow under her hips, and we watched my semen flow to the back of her vagina on the camera. I lay next to her and leaned in for a kiss, which she returned vigorously.

"That was the best sex I have ever had", Sara said. "Knowing we are conceiving a baby here was incredible. And everyone saw it.", she added.

"I know. That was the biggest orgasm I've ever had", I whispered to her before kissing her again.

Sara stroked Makenzie's belly one last time as she got up from the bed and put her robe back on, her massive belly leading the way as she waddled to the back of the classroom.

Jenny proceeded to lecture the class for the next half an hour on the science behind conception and techniques for maximizing fertility before handing each pair of students a specific "sexual assignment" for the week. We were given a pass for the week. Jenny also mentioned that the classroom was open 24/7 for student use, and that rooms 014 and 015 were also outfitted with beds.

Finally, after about a half an hour class was wrapping up. Jenny inserted a plug into Sara's pussy to keep the semen in as we both dressed and returned to our seats, still floating on a high from the experience.

"Should we meet up and do it again?", I asked Sara as we sat back down. "I would love to. Does tomorrow afternoon work for you? My last class ends at 2:30", she said. I nodded and texted her the address of my off campus apartment where we could try this in private for a change.

As Sara walked out of class a fun idea struck me. I hung back and waited until the class emptied before walking back to the black curtained area and peeking in.

Makenzie was sitting on a bed inside. The curtained area was set up as a gynecological exam room, with equipment laid out neatly as well as an ultrasound machine. Makenzie was using the ultrasound on herself.

"Oh, hey there. Check out my babies!", she said excitedly as she pointed to the screen. I imagined this in my future...sitting here with Sara a few months from now. I looked at the screen for a moment with her.

"That was fun today. Sara really seemed to enjoy being with you and I think you did, too. She is coming over tomorrow afternoon and I think it might be fun if you helped us for round two. Up for it?", I asked.

"I had fun, too. Just give me your number and I'll text you later, but I think I am free", she said as she handed me her phone.

"Cool, hope to see you tomorrow. I'm already getting a little hard again thinking about it", I said with a wink as I turned to head out.

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The next 24 hours went by excruciatingly slowly. I tried to focus in class but all I could think about was the day before and watching my cock slide in and out of Sara, what she might look like with a big belly, and what the rest of this class was going to be like. It took all of the willpower I had not to jerk off and save my sperm for Sara.

Finally the hour approached. I cleaned up my apartment and bought some KY lube just in case. Sara arrived first to my place, carrying her backpack with her. This was an assignment after all, and we still needed to log the session. She had dressed the part, in what can only be described as a "slutty schoolgirl" look. Stiletto heels, white thigh high stockings, a too short plaid skirt, and a white button up that was half unbuttoned, exposing her ample cleavage. Some fire engine red lipstick completed the look.

"Wow. I can already tell this is going to be fun.", I said as I took her in. She gave me a kiss as I pointed her toward the couch.

"I could barely sleep last night, thinking about everything that happened. I kept the plug in my pussy for a few hours. There was definitely a gush when I pulled it out.", she said with an excited giggle.

I sat next to her as we resumed our kiss and I began stroking her thigh. A knock at the door interrupted us. "I have a surprise for you." I said as I got up.

I opened the door to find Makenzie standing there. Sara turned and squealed with delight as Makenzie stepped inside, led by her exposed belly under a too short cropped top.

Makenzie plopped on the couch next to Sara, who went immediately for Makenzie's belly. Rubbing, kissing, stroking her breasts. It didn't take long for Makenzie's top and bra to find their way onto the floor and mine and Sara's mouths to find their way to Makenzie's engorged breasts, which were starting to produce a bit of sweet tasting milk. Sara's red lipstick was all over Makenzie's body.

"Mmm...oh my god. Alex, knock me up now, please", Sara said as she tasted the milk.

"You may already be, for all we know. I've never cum as much as I did inside you yesterday, thanks to Makenzie and Jenny. Before we do that though, can Makenzie uh, warm me up?", I asked.

Sara and Makenzie both nodded excitedly. I stood and helped pull Makenzie up off the couch and toward the bedroom, with Sara right behind. We got to my bedroom, which I had cleaned and replaced the sheets for this occasion, and I began stripping down, as did the girls, until we were both naked, save for Sara's thigh highs which she knew I liked.

I motioned for Sara to lay on the bed, and Makenzie crawled on to the bed and immediately buried her face in Sara's glistening wet pussy, which elicited an immediate moan from her. Makenzie looked incredible, her pregnant belly under her and her ass in the air. I climbed on to the bed behind Makenzie and began rubbing my cock along her slit, already slick with her juices.

Sara was thoroughly enjoying Makenzie's vigorous tongue on her clit, her eyes closed and mouth open as she played with Makenzie's hair and approached her first orgasm of the night.

I slipped my cock into Makenzie, savoring the feeling of her pregnant, soft pussy as I slowly slid in and out. After a couple of minutes, Sara's orgasm hit and she gripped the sheets hard as it wracked her body. Makenzie's face was covered in her wetness, who was now moaning in time with my cock sliding in and out of her.

"You better not cum in her", Sara said sternly as she watched me. She slowly rubbed her clit as she watched us.

"I won't. Crawl next to her so I can get inside you", I replied. Sara moved next to Makenzie. I now had 2 beautiful women side by side, their ass and glistening pussies in the air. I slipped out of Makenzie and into Sara, who was wet and ready for me. I held on to the curve of her hips as I moved in and out and she met my motions, causing me to plunge deeper. Pregnant pussy did feel great, but so did Sara.

"This turns me on so much. I remember getting knocked up in class and I've been so horny ever since", Makenzie said as she watched us.

"Wanna try another position?", I asked. Sara nodded. "How about regular old missionary?", she asked. I pulled out of Sara as she flipped over and spread her legs for me. Her pussy was swollen and red. It glistened under the dim light of my bedroom.

I crawled on top of her and easily slid into her pussy. Makenzie moved next to us to watch. I gave Sara a wet kiss as I slid in and out of her. She turned to Makenzie who did the same with even more vigor. We continued like this for several minutes as I slid in and out of her, exchanging kisses with each other.

Finally I felt my orgasm approaching. "I'm getting close", I said as my pace slowed and I plunged more deliberately in and out of her.

"Fill her up. Make her a mommy!", Makenzie said over Sara's moans. With that I took one last plunge into her pussy before unloading an enormous load of cum. I could feel my cock pulsing against Sara's pussy walls for what felt like 30 seconds but I am sure it must have been less than that. I collapsed on top of her as my cock slowly deflated inside her.

After a few minutes I rolled off Sara and Makenzie propped her hips up with a pillow. Sara laid there with her eyes closed and her hand slowly tracing a circle around her belly button, no doubt imagining what must be happening inside her. She fell asleep this way.

I cuddled up to Makenzie, my hand resting on her enormous belly. We occasionally exchanged a kiss but we both eventually fell asleep with her pressed into my side.

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Makenzie and I woke up before Sara in the early morning hours. I could see the pre-dawn sky glow through my blinds start to fill the room, illuminating the two beautiful women in my bed. My cock slowly came to life as it rested against Makenzie. I stroked her enormous breasts, fingering her nipples as little drops of milk formed and I licked them off. It wasn't long before I was fucking Makenzie in a spoons position, slowly and quietly so as not to wake Sara, who was still in the same position as before, full of my cum.

Makenzie and I exchanged quiet, gentle kisses. Her leg was wrapped over mine to give me better access to her pussy. We fucked slowly for several minutes as I kissed Makenzie's neck. "Cum in me", she whispered to me. I picked up my pace a bit.

After another minute or so I exploded in Makenzie. It wasn't nearly the same volume as I had with Sara, but it was enough to start leaking out of Makenzie's pussy. We hadn't been nearly as stealthy as I thought we were, though.

"You two are bad!", Sara said with a playful scorn. "That's my jizz!", she said with a giggle.

"I couldn't help it. You were out cold and she is so hot", I said. "What a mess", Sara said as she inspected Makenzie's cum soaked pussy. I rolled over as Sara took my place on top of Makenzie, mounting her in a 69 position.

Sara eagerly sucked the cum out of Makenzie, her face now covered in our juices, as Makenzie worked her clit. This continued for several minutes until they both came, and then rolled side by side out of breath from their lovemaking.

"Time for a shower. I need to head out" Sara said, giving me a sloppy, cum covered kiss as she strode out of the room to go take a shower.

Makenzie hung around for the rest of the morning with me. We had sex one more time on my couch before she too headed out. What a day. I ordered DoorDash and crashed for the whole day, still glowing.

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The next couple of weeks went by with a blur. Class alternated between lectures and watching other couples have sex. Sara and I continued to have sex every day, even though she was outside of her fertile period, and I think she spent more time at my apartment than hers. Makenzie joined us a couple of times for fun, but was busy with her own class and life as well. Sara and I did our best to try to get to know each other more but the thrill of the entire experience was always there. The secrecy and lust just fueled more secrecy and lust.

Finally, a few days after Sara was meant to get her period she took a pregnancy test in class. Within a few minutes the entire class knew the result along with me: Sara was officially the first student to get pregnant. We celebrated by fucking on the back cot, of course.

It wasn't long before other girls in class announced their pregnancies, and within about 2 months 75% of the girls were pregnant. There was less sex happening in class by this point but it was still ever present, and things started shifting more towards the coursework and analysis.

Makenzie had her twins in mid October and disappeared from our lives for a bit, but Sara and I were still very sexual with each other and it felt like our relationship was turning into a more normal college couple, albeit a pregnant one. We spent more time together as a normal couple doing normal couple things, which felt good. We still hadn't told anyone anything but that couldn't last too much longer.

Sara started showing toward the end of the year, and it was so sexy to see her belly bulging out. Her shirts and pants were clearly getting tighter and we'd need to go maternity shopping soon. We both admired and fetishized her belly constantly, and I often stroked it in class. She seemed to be getting bigger faster than some of the other girls in class, and the first ultrasound confirmed it: twins. We were both excited and twice as nervous now.

Things continued like this until the end of the semester, falling into a routine, until one day after class when Jenny approached us as we were packing up.

"So, twins! How exciting. Sara, you look wonderful", Jenny said enthusiastically.

"It's amazing, I feel sexy with this little belly right now and Alex has been wonderful", Sara replied.

"I've got a favor to ask though. As you know I also like to participate with the girls in class in getting pregnant with you all. I've had sex a few times with some of the students in my fertile period but it hasn't happened yet. I'm ovulating on Thursday. Would you be interested in having sex with me in class?", she asked.

Sara looked at me with a grin. "You kidding? Clear your weekend calendar!", I replied.

To be continued...