A few days ago, I was over my sister's place visiting. It was me (24) her (21) and her boyfriend (22) all just hanging out and talking. After a while somehow the topic of sex came up. We were talking about experiences we have had, things we have tried, embarassing moments etc. She then mentioned that one of the things she always wanted done is to be filmed having sex, not just prop a camera on a table, hit "record" and go at it, but to have someone actually film her having sex at different angles, closeups etc. like starring in her own porno. She then said to me that the only person she thought she could ever really truly trust filming her and to never tell anyone was me. She said she mentioned it to her boyfriend and he was ok with it. I was kind of surprised at her asking me. The thing is, she is a very attractive girl and if I did film them I would probably get totally aroused while filming them, and I was blunt with her. I told her that sex is a very hot sight to see and I might get totally turned on doing it, and she was like "if you really get totally turned on by it don't worry I will take care of ya". Should I go ahead with it or what? I know its kind of a weird situation with her being my sister, but we are all adults, and think we can handle it, just looking for some advice on this one. Thanks!