My stepsister thinks I'm gay. I told her I'm not, and that I'm just shy around girls, but she doesn't believe me. Last week, she called me into her room and point-blank asked me if I was into guys. When I told her no, she made me prove it to her by jerking off in front of her while she showed me her body! I have to say, I was definitely turned on... but when she told me that she was going to have her boyfriend come over so she could teach me to suck cock, I totally blew my load.