About 5 in the afternoon I heard the front door slam. I pulled my penis from Mommy’s throat, letting her breathe again as my little sister called out that she was home. The last two hours had been wonderful. After getting Mommy pregnant with my lover’s children (I knew they were his, not mine), I’d spent the rest of the time getting her as full of my semen as possible before trying to cover her with it. I’d been pretty successful, too. The bed was slick and smelled of our juices, Mommy’s hair was matted and crusty, and we’d been rubbing her body all over to spread out my cum.

I liked having sex in Mommy’s bottom a lot. It was so tight and I didn’t have to keep stopping to let her breathe like with her mouth, though I liked how her tongue made me feel too. After I’d filled up her womb, I hadn’t experienced the same intensity of feeling, almost like I was trying to save up cum for what it was intended to do, but it was fun putting that buzzing plug in Mommy’s bottom to keep all that cum there. I scolded her for not being able to keep it all in herself, but her solution proved to be even more arousing.

As we heard my little sister rummaging around downstairs, Mommy called to her through the white bubbles she kept burping up from all the semen in her tummy, telling her to come up when she was ready. I was almost ready to pop again, so I (or was it my other self? I couldn’t tell anymore) forced her face back on my penis and pushed down her throat. When I heard her choke and moan at the same time, the cum already in her stomach spilling past her lips, I lost it and began filling her throat for the third time. I was so proud of Mommy when she tried and tried to swallow more, but she just couldn’t fit any more in there. It started to gush from her nose as her eyes rolled backwards as she came, and I pulled out to spray her down again. I loved seeing Mommy coated in cum, sitting on her knees while shaking in delight, all the while holding her bloated tummy.

After a few minutes, we heard my little sis coming up the stairs to check on me. When she got about halfway up, she stopped, and I smiled knowing she’d encountered the smell of what we were doing. It might have grossed her out under normal circumstances, but this was full of the same pheromones I’d used to turn Mommy into my new toy. A few tentative steps later, she was at the door, her voice almost dreamlike as she opened it to reveal the scene.

She was only a year younger than me, but with brownish hair and eyes like Daddy. About three inches shorter than me, she was about as skinny and was even further away from maturity than I was. Her school uniform, the same knee length plaid dress, white cotton button down shirt, and knee socks I had to wear just added to the image of innocence I found hard to resist.

I knew I had to let her be the one to make the first move, give me signs that what I wanted to do was what she wanted too. It was all part of the entrapment. Thinking back, I probably should have been worried about these thoughts and the use of words I hadn’t really known before, vulgar or otherwise, but it seems so trivial now. All my attention was focused on the confused look of undefined desire that was firmly planted on my sister’s face.

She looked at Mommy and me, and I knew she could only see what she was prepared to. That’s how no one had been able to see how huge my tummy had been his morning. She walked in slowly, seeming to try and form words but fighting through the fog her mind was in now.

Mommy was too full of cum to talk, having coughed up just enough to let her breathe but the sticky slime still coating her vocal chords, so I greeted her first. It was probably as surreal as one could get when I asked her what I missed at school. I didn’t really care, I just needed her to stay and get a nice, big lungful of what I later learned were called aphrodisiacs that hung in the air. I didn’t really have to worry, as I got half muttered sentences and a glazed look that fixated on my boobies. I smiled at her and moved in, slowly pulling her towards me and getting no resistance. When I kissed her like I had Mommy, she just stood there and let me do it. After a bit, she seemed to figure out what to do, pressing back and even adding her own tongue to the mix.

It was so hot, I could barely stand it. But I had to. Mommy had been exposed for hours, and I had no idea how quickly the higher concentration would fully bring my little sis under my control. I pulled away and asked if she’d like to try kissing Mommy. The dazed half grunt seemed to say yes, so I brought her over. Mommy got up on her knees, bringing her face about to my sisters, and I watched the two of them make out. The cum still on Mommy’s lips would accelerate the change, and the way she smeared the coating on her body all over my sister’s face and clothes had me aching for another cum in moments.

Then I saw Mommy put her hand on her stomach, above her full womb, and press down. A rush of my cum flooded from her mouth and into my sister’s, causing her to gag a bit as Mommy held her tightly, keeping their lips together. Needless to say I was very upset. I pulled Mommy away roughly, throwing her to the ground before taking her place and pushing on my sister’s stomach, forcing her to regurgitate most of what she had swallowed into my own mouth.

Thankfully, the look in her eyes was not of fear, but of insatiable, if unrecognized, lust. I apologized to her for Mommy’s behavior, and told her I’d make it up to her soon enough. With that, I turned to Mommy and looked at her angrily. The look she returned reminded me of a disobedient dog knowing it was in trouble.

I knew she was merely trying to help me in the seduction as she promised, but I still had to teach her that she was not to do anything without my permission. A wicked idea crossed my mind. Now that her stomach had room, I told her that her task was to clean the bed of our past love making. She had to clean it all up using only her mouth, would not be allowed to cum till I said so, and before I wanted to use it again, or she would get a real punishment. She went to work immediately, the sounds of her slurping up my semen and both our girl cum filling the room as I turned back to my little sis.

She was rubbing her hands on her crotch through her skirt, confused as to what to do but a complete slave to her body’s need to do something, anything. I instructed her to undress slowly for me, and she did, seeming to realize my and Mommy’s pregnant bellies for the first time as she unbuttoned her shirt. When she stood there naked before me, I let her touch my tummy, and told her to kneel down to kiss it. She did enthusiastically, even stopping to lick my bellybutton clean of my cum.

If it was gonna be this easy to spread my lover’s genes around, every woman in town fit for childbirth would soon be just like me. I loved it.

I felt my penis shift again, and I knew it was reforming to fit the new breeding mare (new words and phrases again) I was about to fill. I heard my sister gasp before I felt her small hands wrap around the shaft. I was a bit sad I couldn’t see my penis past my belly, but the look on her face was priceless.

I reached down and pulled her up, pushing her so that she set her hands on the bed frame, her tiny butt pushed out towards me. We watched Mommy still slurping away for a few moments (she was making good time) before I told her to reach back and make sure I hit the right hole. I had an enormous load brewing, and her womb was getting every drop.

She did as she was told, and I felt the tight, wet lips of her unused kitty rubbing against the head of my penis. I remembered how much it had hurt my first time, so I knew I somehow had to convince myself to go slow. The first push got a groan of pain and pleasure from my sis, the second and third got the same. I kept pushing a bit harder each time, telling her to spread her lower lips before I finally, after at least a minute of trying, got the head to move in most of the way.

She was so tight I had to concentrate on not blowing right then and there. I hadn’t even gotten the head in and I was ready to fill her as never before. I pushed harder, again and again, till the head popped in completely. She groaned again, more in pain this time. I told her to play with the little nub atop her kitty, and the stretching of it by my penis made the button easy for her to find. I felt more and more wetness around my penis, and I kept pushing and pushing. I hit her virginity, making her squeal as I had. I held her in place for a moment, letting my precum wash over the barrier for a bit to lessen the pain.

After a minute or two of hearing Mommy still slurping, I thought it best to get it over with quickly, so I pulled back suddenly and rammed through. She squeaked through clenched teeth, but I knew she had liked it more than it had hurt. The remains of her torn virginity helped me as I slid slowly but surely further in, finally coming to rest against her cervix. Letting my precum build against it as well, I could feel it loosening around the tip, slowly opening up to let me through.

She screamed again, this time in orgasm, as the rest of my penis slid into her womb. I pulled her back, exposing her tummy to Mommy, and showed the woman who had borne us both the large bulge my penis made in her youngest daughter’s stomach. I pulled her head back, forcing her to arch around because of my own bloated womb, and gave her another sloppy kiss before letting her go and beginning to ram into her mercilessly.

I called her all kinds of dirty names, the kinds of names normally not said to a family member. I told her she was my bitch now, and explained all about how I was gonna make her bear my babies for the rest of her life. I told her how her breasts would grow out to make milk for them, and she’d cum as our babies suckled them and I filled her womb with another batch. I told her she’d beg for it every time. Judging by how hard she kept cuming, I was pretty sure she loved the idea.

I reached up and grabbed her hair, pulling her head back and letting her scream her joy, lifting up one of her legs and placing the ankle on my shoulder. She braced herself as best she could, trying to reach down to my tummy as she begged for my seed but being forced to hold on for dear life through the force of my thrusts.

I could see Mommy was clearly having trouble slurping up the rest of the cum, probably another cup or two, as her belly filled back up, but I gave her an incentive. If she finished up before I did, I’d let her hear me impregnating my darling little sister, and maybe cum at the same time.

It did the trick. Mommy forced her stomach to hold more as she sucked it all down. I could see it pooling in her mouth, blocking off her airway because there was nowhere for it to go down. I called her over to me, my sister still screaming in ecstasy beneath me, and let her drool as much as she needed to into my hungry mouth so she could breathe. No more, though. I wanted her stuffed full. I couldn’t put a plug in her throat, so I had to keep an eye on Mommy to make sure she was well behaved.

She then moved and put her ear against my sister’s tummy, moaning in joy as if I was pumping her as well. It was too much for me. My hopes to hold it back just a little longer were dashed when I heard my sis tell Mommy how happy she would be to be knocked up like this. I screeched in ecstasy, telling Mommy just in time that she could cum too, before the first squirt flooded my sister’s womb.

It was even better than when I’d impregnated Mommy. My toes curled and my hands left large bruises on my sister’s skin as gush after thick, sticky gush rushed into her. A pure eternity of bliss unlike any I’d experienced since my own impregnation, and perhaps greater. I wondered if it was just me getting better at it, or if it was that she was a virgin. I couldn’t tell which I wanted more.

I watched Mommy through the stars I saw, shaking hard as her head was pushed outwards by my sister’s rapidly expanding belly. Thankfully I had the presence of mind to pull her out of the position she was in and put her on her back on the floor. It might have gotten really painful otherwise as her belly kept getting bigger and bigger.

Mommy actually started to get a bit worried that I might hurt, or even kill her. The size of her belly was already almost as big as ours, and I was still coming. Something told me she’d be fine, and it hadn’t let me down yet, so I told Mommy to be quiet and help me finish.

She reached around beneath us, still wearing that concerned mother look, and began stroking my kitty and running her nails across what little of my penis was not buried in my sister. The inflow of cum increased again, and my sis grunted from the stretching. She looked absolutely absurd now.

I finally stopped cumming shortly afterwards, and looked in amazement that my sister’s womb bulged obscenely from her body. She rubbed her hands up and down it, staring in amazement at the perfect orb that had contained my massive orgasm. I felt a little jealous for how much she’d gotten.

Then it started. Mommy and I could see it. My sister’s eyes rolled back and she started cumming again as she saw her newly matured eggs being fertilized by the hundreds. We put our hands on her, the image flooding our brains as well and driving us to orgasm along with her.

We didn’t even think to wonder how she’d be able to go to school, much less walk, like this. It seemed such a secondary concern. Daddy would be coming home soon. I had no idea how he’d react to the pheromones or to this scene, but I knew it would be an experience to remember.