Watching Sister

Once I was younger I watched my sister giving her boyfriend a lapdance and jerked off to it. Her boyfriend brought her home after they went out and they were on the patio behind the house. I was up on a platform that was built in a tree in the backyard and covered with an old canvas tarp to keep out the weather. I should of been in my room but it was hot I snuck out and climbed up on the platform to enjoy to cool night air.

They started making out and he was feeling her up and asking her something I couldn't hear. Finally she took his dick out and lowered her jeans part way and gestured for him to get behind her. She was bent over staring through to window into the house probably making sure no 9ne was coming.

Her bf started grinding his dick in her asscrack while she gyrated. I was up on the platform watching and started stroking my dick. He held her hips and was pounding her ass finally he pushed forward nearly throwing her down and shot 3 ropes of cum on her lower back. I came almost immediately after. Sometimes I think about it and jerk off still. Kinda twisted but it gives me one of the most intense orgasms every time.