No but im in my 30's and my half sister is in her early 20's and i have been gone for a long time with college out of state and then working out of state but anyways when no ones around shes very freindly and touchy with me. Three times i had to get up and leave cause she was making me hard, usually by sitting next to me and brushing up against me or nonchanlantly putting her hand on my thigh while leaning over to look at something. She always wears very sexy/revealing clothes too, like short shorts and a tube top. One time she leaned over behind me and was brushing her breasts across my back with no bra on, i could feel her very erect nipples like two eraserheads brushing against my back. I really tried not to get hard and was like 'oh god no in my head' but i was so aroused i got incontrollably hard and at the same time i felt really embarressed and ashamed so i said i have to goto the bathroom and got up. She looked right at my bulge but didnt say anything. After that i noticed she glances at my crotch like shes seeing if i get hard or not and when i do i get up cause im scared she might think im some weirdo. I havent touched her back or anything like that at all. Previousely to these instances we have never messed around at all or even talked about sex or anything. I dont know if shes being like girl friendly and thinks im a freak or if shes doing it on purpose.