Sis and I swinging

My sister and I are 31 and 32. She and I have lived together all our lives. At 17 our parents were in a car crash and died. I was 18 and took the responsibilities and with insurance the house was paid, car was paid and there was money already set aside for college. I got a couple of part time jobs to arrange hours around college. She and I both felt better staying in town for college. Shortly after the funeral my sister began sleeping with me in my bed. It took probably a week but I just told her she was too damn hot looking for me to sleep with her. She noticed my hard cock during the nights, and in the mornings. I knew she was still a virgin though she had given BJs. That night I came home from work after school and all my things were moved into our parents bedroom. In addition there was a new bed in there, new furniture. Then I notice our moms closet was full of my sisters things. "We're sleeping in here now" she said. I reminded her that I couldn't stay sleeping with her. My sister is lovely, very very pretty face, long black hair past her shoulders, very shapely body, and very fit. I'm a legs/ass man and hers are so damn beautiful it's ridiculous. Her comment back was "So, let's take care of that now" she took off all her clothes and standing naked walked over to me and kissed me. "I love you, not just like a brother, I really love you" and kissed me again undoing my pants. She went to the bed, and I took off the rest of my clothes. She sucked me hard, I ate her pussy. I had to tell her to relax and let it happen and finally after another 15 minutes she orgasmed. She couldn't get enough, I licked her again and when she was about to cum I moved up between her legs and pushed my cock into her pussy. I fucked her, kissing her, sucking on those nice pinkish brown nipples. She finished her orgasm, and I couldn't hold much longer. I shot my cum up my formerly virgin sisters pussy. After I was worried about birth control. She told me not to worry she had finished her period only two days before. But after this we need to to do something. I had some blood on my cock and there was a little on the sheet. I leaned her back from her now sitting position and looked at a little blood trickly in the folds of her inner lips and hole. I put my finger in, and when I pulled out I could see my cum following.

So that is how it started. My sister and I have stayed together, like husband and wife. We didn't risk having kids, even though she wanted at least one. As with a lot of couples we started experimenting. Threesomes, mmf and ffm, and then finally about a year ago with another couple. All of us fit and trim, in good shape, and both women totally beautiful. My sister takes cock in her mouth, her pussy and her ass and has for years. The other woman is a 3 hole girl also. The four of us split up with each others partners at first, for several get togethers, then the girls just started with each other. Soon it was all four of us playing together. Eventually he and I would have sex to let the ladies watch as well. It was a relationship where anyone would fuck anyone else at anytime and no jealousies. I let it slip in front of them both, I was fucking him in his ass, him on his belly, and I called out something to my "Sis". The wife said that was cute, asked if it was a roleplay thing, and we told them.

After that things got hotter. The other couple really enjoyed watching me and my sister fucking, buttfucking, eating each other. They talked about how hot it was that he was not only fucking my "wife" but my sister too. The loved talking about brother and sister fucking each other. Evidently the two women got together talking, the other wife is 28, they both were ready to get pregnant. Their cycles were not in sync. So with all 4 of us in the room, my sister and the other husband playing with each other, they watched as I knocked up the wife. Then two weeks later she and I watched as the husband knocked up my sister.

We will each have our child and raise them as our own. This way we don't have the risk of genetic problems with our baby. At least not the obvious ones that could have occurred. I love fucking both pregnant ladies, for some reason I get off more fucking my sister in her ass while she's pregnant. I even took her out of town for business and in a hotel room, drapes opened, lights on at night. Everyone in the neighboring tower could see me fucking my sisters ass with her big pregnant belly hanging down. She came 5 times that night.