When I was hiding under the bed to surprise my sister with a little mischievous spirit...I saw my sister changing clothes, masturbating, having sex with her boyfriend, and the appearance of my sister that I don't usually see! - When I think of something erotic happening right above my head, I get so erect that I can't even come out! - My sister found out when I was looking at her with my dick hard! - I thought she was going to get mad at me, but when she saw my erect dick, my sister got excited too, so she pushed me down on the bed and we had forbidden incest!