I confess I don't know what to do. My bf and I had a deal where we'd do each other's biggest fantasies. So him and his friend D/P'd me last week. Only, his is that he wants me to be mounted by his "best friend" if you know what I mean and I don't want to do that because it's wrong and stuff.
How do I say no in a way that doesn't make me look like a selfish whore?