If penetration was discussed in advance and agreed upon, then you have every right to expect it. If the escort tries to pull a switch at the last minute, I would not engage in haggling. The encounter must be voluntary for both parties. I would not use the threat of withholding cash to coerce a man into performing an act -- for whatever reason -- he says he doesn't want to do. I wouldn't hesitate to tell him that his fee will be reduced.