I had been married seven years and had two kids when my little sister came to live with us. From the beginning she was a tease and always getting on my husband. She showed too much skin and refused to wear a bra at breakfast. I warned her that if she kept it up he was going to take her and fuck her. Her behavior got more and more out of hand and one day while we were sitting in the game room watching t.v. he slapped her ass and she responded by mooning him with her big fat ass.

His response was to take her and push her down on the bed in her room and he got on her and told her to kick her pants off because she was going to get it. I managed to get up and pull the door closed and didn't watch her get fucked. When she came out she I told her to go back and clean his dick, if she didn't have a towel to suck him and use the pillow case, to always clean his dick after she got fucked.

He pulled her into our bed and put her under his arm and kept her there. She slept there and got fucked there. For the first several weeks the only participation I had was to suck him clean afterwards and dry him off. Her entire behavior living with us changed and she became part of the house, she helped with the kids and kept up with her share of the daily chores. She even got a part time job as a receptionist at a vet's clinic in the neighborhood.

Our mother had some legal problems so my husband went to help and my sister and I had the house for ourselves and that night we talked. She slept in my arms and I asked her if she liked having a man hold her every night and if she liked getting fucked. I also asked her why she never gave him tits, she always only gave him her ass and he got on top of her from behind. I told her she had nice tits and if she was going to sleep with him she should make an effort to give him tits too.

Over the next year we learned how to sleep together and to help each other during sex. When he took one of us, the other helped getting up to an orgasm, including taking matters into hand and breast play and clitoral stimulation, after the orgasm came, we traded places so he had a vagina to cum in. During sex we got a lot of pleasure if we could get the other one to orgasm, I especially liked playing with my sister's tits and sucking on her nipples or her clit. She on the other hand was into slow massage and stimulation while I was getting fucked. We never played with each other with out him being present.

Ten years and we are going strong, she has had a kid of her own and we are as close as ever. The one thing that changed is that she grew up and her flirting is not as spontaneous, although if she gets in the mood she can get him to chase her into the bedroom. I love my sister, much more than I did when she came to live with us. I never got jealous of her, not even when she was flashing her butt and tits around.