When someone won't agree to do something unless they know for sure that the outcome will be how they want it. (they're not willing to take a risk)
"mike won't ask out that girl unless he knows she likes him"
The name of a stipulation put in Hulk Hogan's WCW contract which gave him the power to decide entirely how his wrestling matches were going to play out.
Does HHH have the Hogan Clause in his contract? No, he doesn't, but he sure acts like he does.