I was about twelve years old, when one day I came back into our house after playing with my friends. I didn't think anyone was home, and as I'm walking to my room, I pass by my older sister's room. She was probably seventeen or eighteen at this time. I see her and her boyfriend, and there both on her bed, and they're naked. They don't see me because they're too busy fucking, and I'm fascinated by what I'm seeing.

Anyway, I stop and watch, mainly because I'm sort of in shock. I hear my sister groaning, like her boyfriend is hurting her, and I start to think that maybe I got to get him off of her. But it's not like she's fighting to get him off. She's got her arms and her legs wrapped around his body real tight, and it's more like she's wanting him to hurt her more.

I continue to watch, and I see that he's pushing his hard cock in and out of my sister's body. At first I thought it was her asshole, but then I realize that he's sticking it in her pussy. Next thing I know my sister's boyfriend starts to moan real loud and he arches his back, like he's the one in pain now. And my sister, she starts to moan real loud too.

They stay like that for a few seconds, and then I see her boyfriend pull his cock out of my sister's body and a whole lot of cum is dripping from his cock. Now my sister gets really pissed off at her boyfriend and tries to get off of her bed. That's when she sees me, and she screams at me asking me how long I've been there, and what did I see.

Well, let me tell you. I took off like a bat out of hell. I made it out the door just in time because her boyfriend was right on my heels. I didn't come back home until long after my sister's boyfriend had left. My sister was a lot calmer then, and she wanted me to promise that I would never say anything about what I had seen. I said that I would, but I wanted something in return. I wanted her to teach me how to fuck.

That request didn't go over too well. My sister had me in a headlock before I knew what had happened. Death threats filled the air as we continued to fight. Finally I got the upper hand on her and my sister relented and said that she would teach me, once, how to fuck a girl.

My sister put it off for as long as she could, but finally she did let me fuck her. She wanted me to wear a condom, but I told her that if her boyfriend didn't have to wear one, neither did I.

Our session started off pretty bad. I couldn't get hard, and my sister refused to do anything that would make me get hard. Finally, just to get it over with, my sister sucked on my cock and the next thing you know, I'm as hard as a rock. At first, my sister was simply laying there like a dead person while I did all the work, but finally she started to loosen up. By the time I came, my sister was rocking and rolling and moaning as if her boyfriend was fucking her.

My sister still says that she doesn't like what I made her do, but deep down, I think she had fun. I know that I did.