When we are in a game forcing auction and the opponents interfere (usually to sacrifice) it is clear that we are not going to go quietly and just let them steal the contract. If the opponents bid over us, then we will either double them and defend or bid on to our game. Forcing Pass is an agreement used to help us work together with partner to make a good decision about which to do.
(526) Fits and More: Raising Partner's Overcall
(525) Fits and More: 2-Way Reverse Drury
When partner opens in 3rd or 4th seat and we have a good hand, we do not want to go jumping around to show it – partner may have no game interest for their opening bid. We want to have an effective way of describing our good hands cheaply when partner opens in 3rd or 4th seat. When partner opens 1-Major and we have a maximum passed hand with a fit, then we want to be able to show this to partner without getting too high. This is what the Drury convention accomplishes.