I love to do this. There is a really hot daddy bear type that goes to the Y where I used to work out. We both went very early in the morning and he always took like a 20 minute steam and shower. He would leave his locker wide open with stuff spread all around, so I would grab his clean boxers hide behind the lockers, put them on and jerk off making sure to get some cum on them just near the fly. then I would put then neatly back where I found them. I always had the best orgasm doing that. After I did that I liked to hang around the locker room and watch him get dressed in those boxers, knowing he would have my cum on him all day. He never noticed the wet spots. I guess he just thought it was some water from the shower. Little did he know