Me and my ex girlfriend use to fuck all the time. We were friends with benefits until one day she decided that she didn't want to anymore. Well, her sister called me and asked me to come over and I thought my ex wanted to be friends with benefits with me again so I went. My ex wasn't there, but her sister, she was extremely hot,was in her underwear and moaning my name. I ask what is happening and she said that she and her sister talked about the sex I had with her and since we were finished the sister wanted it too. I was totally okay with it so we had sex for a few hours and then my ex got home and her sister was making out with me naked, stroking my cock. My ex gasped and left and then her sister took a picture of us fucking and left it on her dresser so my ex would see.