preemptive pee

the act of forcing yourself or others to urinate in anticipation of not having another opportunity to do so for a long period of time.

Better take a preemptive pee before we hit the road.

Preemptive Pee Break

The act of going to the bathroom before your actually need to so that you do not have to go later.

Joe: I’m taking a preemptive pee break before the moive starts so I don’t miss the climax.

Tom: Good idea, I'm right behind ya man.