I was sixteen years old and I had to stay alone with my twelve year old sister and one of her guy friends also twelve as their baby sitter. Since it was about nine, I told my sister that it was time for her to send her friend home and for her to go to bed. My sister said, “No,” and I began to grab her by the hand to drag her to take her to her room and asked her friend to leave. Her friend decided to say he didn’t want to leave and then tackled me and knocked me to the floor by surprise. Then my sister began to hold me down while he unbuckled my belt and pulled down my pants and then my underpants leaving my thing exposed. Although I am taller than both of them, I have had a late development in puberty down there so I have a half inch penis when I’m not arouse. He laughed and so did my sister and then pulled down his own pants and underpants while I was still on the ground and showed me that his penis was about four inches long even though he wasn’t aroused. My sister then started teasing me about this, and he continued to as well and it was very embarrassing. She kept holding me down while he moved around and then began slapping my face with his penis. I didn’t know what to do, so all I said was that they could stay up late and he didn’t have to go. The then got off me and let me pull up my pants and then said that I should go to bed, but they’d wake me up when our parent got home. I was humiliated at being sent to bed by them, but they did get me up in time and I said they had been so well behaved. My sister still teases me about my size whenever our parent isn’t around. Particularly when we’re around people my age. It’s very embarrassing!