The practice of leaving the washroom with wet hands, usually down to not being able to use the hand dryer. Generally happens in mensrooms to avoid guys having to hang around uncomfortably whilst they wait for a dryer to become free.
Katie: Boy you're clammy. Are you nervous cuz this is our first *proper* date?
Chet: Get over yourself. It's just the result of a damp-out. Dryer was out of order and these are my best khakis.