We learned this the hard way after a couple unpleasant hook ups, where the guys attempted to be insulting to me as they fucked my wife. Both seemed confused because we had listed our self as a cuckold couple, and thought that meant we wanted a "bull" and all that stuff.
Don't get me wrong, I can get into a little light humiliation, but only at the hands of my wife("Oh honey, his cock is so big, it feels so good", not "Sit in the corner and jerk your little dick loser"lol). The distinction is subtle, but important to my self esteem, I guess. I don't perform 'clean up' or 'get him ready' either. Not to knock the ones that ARE into that stuff. Lord knows, I'm not in a position to pass judgement on someones sex life.
So that's why. I think it's helpful to the guys too. They don't show up with a game plan for failure.