My younger sister, who is always innocent and loves me, is actually in trouble because she is extremely aggressive as a member of the opposite sex! Anyway, when I was avoiding her so that she wouldn't find out, my girlfriend's younger sister mistakenly thought that she hated me and stormed into the bathroom, saying she would wash my back in order to get closer to her! I got an erection from the feeling of my sister's swollen breasts and skin rubbing against each other, and I thought she would hate me, but I was intrigued by the fact that she got an erection for me.