Obligatory Handwash- n. 1. When you're in the bathroom with someone else and custom forces you to wash your hands.
You know your D isn't dirty. You know you've done nothing during this bathroom experience that merits a handwash. You know all this. But society doesn't. So you get done peeing and think you're home free, then douchebag walks in and you're like, "Fuck. I've gotta do this now". You break path and try to make it look like you were walking to the sink and soap all along. While you're washing your hands you might look at the guy via the mirror and give him the "We both know why I'm doing this" look.
If it so happens that you and another both finish peeing and approach the door at the same time under the assumption that you're both alone, two things can happen. You can both work your transition techniques respectively and partake in a O.H., OR you can comMANicate. After noticing each other, you both pick up on each other's dejected sigh and aura of frustration and instead of working your transition you give each other the go ahead nod. A sort of "This is Maverick requesting flyby" , "Flyby approved, Maverick" kind of thing. The G.A.N is a sign of mutual trust and to rat on a fellow brother's skipped sanitization after giving a nod is a grave offense.