Post Up

1. The act or request for one party in a betting agreement to present or prove that he has the money to settle the wager in advance. A facet of some sports bets and prop bets.

Post Its

When does "posting up" become a requested or expected aspect of a bet?

Usually when one of the people making the bet either has a low level of credit-worthiness or is likely to go broke by the time the best is to be paid off. This usually works in conjunction with a high likelihood that the other betting party does and will have the money when it comes time to settle.