Ohhhhh.... in that case here is what you should do. Try it out, but you need to video tape it and send me a copy.
Seriously though, yes, it could ruin your friendship, but if both of you are mature enough to handle it you could try it. Just remember, that once you have a sexual relationship with someone, the unexpected can happen, and sometimes emotions develop that one or both of you did not want to happen, and it could permantly change your friendship.