Topping from the bottom... I don't get it. Maybe I'm more sensitive to it because I've always done role play. Especially seeing a Mistress for the first time we will either discuss the session in general terms on the phone, in person or via email. Some have gotten skeptical, or said they were after session, because they had clients who scripted the whole thing out with dialogue for both of them. What's the fun in that?

Sessions should be spontaneous, filled with anticipation.

The only "control" the sub should have is explaining, clearly before the session, which activities he or she is comfortable with and which are off limits. The sub also has to clearly understand what the limits of the Mistress are.