I find myself having to do it all the time. I am comfortable with it usually but it gets annoying going to straight clubs or things like that becuase I know I will feel uncomfortable telling strangers I am not interested in them.
I hate it when people assume that becuase I am gay I am open for threeways or things like that. Guy's often ask me if they can watch me having sex with my girlfriend. This makes it really alkward for me and I just want people to understand that they wouldn't want to be watched having sex with the person they loved so why should I? Ahhh sore point for me : (