I was just sat on the stairs randomly when I noticed that my sister had gone to her room after having a shower. I have always liked my sisters body so I decided to look through a mirror just outside her room that lets you see in.
She took off her towel and I could see her blonde pubic hair and her tits that were a nice size. She had had one of her nipples pierced. I was feeling very very horny so I decided to wank right there. I started pulling my dick all the time watching my sisters body then while I was cumming she came out of her room and just looked me straight in the eyes and smiled. Then she walked off, she still hasn't spoken to me about it.