My step-sister and I have always had a pretty good relationship. We talk about most everything easily except one thing. A long time ago I made her be part of one of my sick fantasies while I jerked my cock nearby. I didn't harm her at all, it wasn't like that. All I did was convince her we were going to play a fun game and had her undress to her panties and stand against a tree in our back yard. I then tied her to the tree and left her standing there for oh, about half an hour while I went inside the house and looked at her through a window while jerking my cock to pop.