How's about "I'm in control" vs. "you are in control" ? My instructors always applied these phrases, expecting me to confirm with the reverse. And only the one confirmed by both to be "in control" would touch any control. Simple, effective.
But, as hinted before for the topic starter, I may have been lucky with the instructors I happened to fall in with. The more I think about it, the more likely it seems. They both deserve big kudos from me! (@Martin & @Roger)