We are watching my wifes cousins (11 yo girl and 8 yo boy)for the week while they are on spring break. Since there parents went on a trip. I work second shift and my wife works 3rd so heres what happened: I got home at midnight kids a were in the bed I stripped down to my boxers Wife git dressed and left. I was watching tv and browsing some porn when the 11 yo popped in saying she could not sleep and crawled in my lap. I tried to hide my boner and the porn but she was already looking at the screen. Seh asked what I was looking at I said uuummmm... have you had the sex talk with your mom? She said oh yeah about where babies come from a man pjts his penis in her vagina. Good have you ever seen it. She said I sneak down the hall and watch and listinto mom and dad sometimes I like to plah with my nipples when I listin ttomoms moans she likes to tell dad to suck on mommas titties its hot. But they usually have the light off. I said okay and showed her some amateur mom and son videos then she wanted dad and daughter videos. She was rubbing her budding chest I could smell her pussy. She said im getting a feeling down there mom told me about its like a buzzing feeling. I took her hand and showed her where to rub. She like it alot then she wanted to see my cock. I coulnt resist I showed her. She said its much better in person. Lets have sex I turned her down and told her we cant do that it againstthe law and wrong. She was looking hotter and hotter. Finally I said okay no sex but it will feel good so take off your pantiesi took off my boxers had her climb on top of me and grind her pussy on my cock. I had her slide back and forth on my cock her pussy was so wet she ripped her shirt off and was playing with her nipples and and loving it I pulled her forward and sucked her tiny tits. She pulled back to grind hard on me the middle of my cock was on her clit I gave her short thrust soon enough she was cumming on my cock. She said wow now I know what mom meant. I said it only gets better. She really wanted me to fuck her and I lost all will power and tried to stick it in but all I could get in was the head of my cock that was it. She was very tight I said sorry it wont fit and im not taking your virginity she said I liked that do what you were doing. So I continued and it felt great I seemed like it lasted forever her little body pushing back on me. Then I blew my load right there in her pussy. She came when I came and then almost immediately said what if im pregnant I said dont worry I had a vasectomy so I cant make babies any more. She smiled and said this is our little secret dont tell anyone.