Personally I wouldn't have a problem with a guy grabbing my cock altough I'm not gay/bisexual - but I'm very secure in who I am. Maybe its because I'm from Europe, but I went to a club in canada once and there's a trick we do with friends overhere in europe - You tell your (unknowing) friend to give you his hand and then you put it against the ass of the person standing in front of you real fast so he can't stop you. Unfortunately doing something like that in canada isn't considered humor, it's considered enough to get a bouncer jumping you
And I suspect the same in the usa.
What I want to say is, I think most of you are too 'sue the bastard or bash him into oblivion'-minded. And admit that when you would be sitting with 3 hot babes in a hottub and one of them would discreetly be all over you - it would be hard to resist. Altough I wouldn't want to sit in a cummed hottub either.