A precautionary pee is when you go to the bathroom to avoid a possible stop that is less convenient later down the road.
Him: Hey - we're about to pass a rest stop. Do you have to go to the bathroom?
Me: I don't think so - stop anyways, I'll take a precautionary pee.
Me: I don't think so - stop anyways, I'll take a precautionary pee.
by Siouxsie Supertramp September 13, 2020