This happen back when I was a freshman in High School, and my sis was a senior. Me and my sis never got along, but she was hot. She was 6,1" 125 and had somw very nice tits. I remember jacking off in my room image I was fucking her.
There have been a few time I had slide into he room while she was sleeping. Just trying to get a good look or a quick feel.
the one good thing was my sister was a hard sleeper, so I was able to do a lot of things. A few weeks have past and I want more then just look and feel, but I did know how I was going to do it. Until one Saturday my sister came home trashed. She came trip throught the door, I was asleep in the chair when she came home. I wokeup as she try to walk to her room. I knew she was wasted and then it can to me to try tonight. A few minutes pasted and I went to my room. So I could check to see if she had lock her bathroom door. See are rooms are joined by a bathroom. Luck for me she just pastout on her bed. This was it my chance, so I when and locked her door. I did not want my parent to wakeup and open her door. I then went over to the bed and help my sister under the covers. After that I made my way onto the other side of the bed. I slowing role my sister on her side, so I could lay right up against her. By now I had the biggest hard on. My cock was just like steel and wanting to be inside her. I then pull her g-string off to the side. I could feel her pussy lips as my cock head rummed against it. I slowly started to work the head between her lips. I her hear start to moan as I went deep amd deep inside her. I could feel her pussy get hotter and hotter. I move in and out slowly feel every inch of that pussy I dreamed about. God my cock felt so good in her and I want to cum inside so bad. But then I thought about her ass, and what that would be like. I then slowly pulled my hard cock from her hot wet pussy, and move toward her ass. I slowly work then head of my cock into her asshole. I could feel the ass tighted up, but my cock was cover in her pussy juice so I just  push it in. God her ass was unbelievable. I was only able to fuck it for a second before I started to cum. It felt like I was never going to stop cummin. I slowly pull it out of her ass and just lay there. I then  head to my room and went to bed. The next morning I was in the bathroom brush my teeth and my sister came in. I asked here how was your night and the I smile. She looked at me and said " Don't tell mom or Dad what time I got home & I won't tell them what you did last night".