I was a 16 year old boy when I pulled down my sisters bikini bottom at the pool in front of my friends. She was 14 at the time and got so embarrased that all my friends got a good view of her butt and pussy,she promised revenge. I thought she was going to soon forget all about it, but months later she got me back good. I had forgotten all about that incident. One day, when our parents were out, she had invited a group of her friends over to the house and told me if I wanted to watch a movie with them. I sat with them and as she slid the CD in the machine. There was no title or music, just me naked masturbating in my bed. It went on and on till I came all over my chest. I have never been so embarrassed in my life, sitting with her friends blushing like crasy. She was saying it was "pay back time" She had copies ready to be ditributed to every girl in school if I din't do exactly what she told me to do. I had to strip naked, lay on the floor and yerk myself in front of all her friends. I had to do it quickly before our parents came home or she was handing over the CD next mourning to everyone. I did exactly what she said but was so embarrassed and nervous by being watched by all her friends, that I just couldn't come. She gave me the CD but I'm still not sure she keept a copy. Every time I see her friends I get embarrassing remarks about that day. I'm sure she's planning something else.