I use posters as a classroom management tool for primary grades. The pictures and words help to build literacy, and remind students of expectation when they are not readers yet.
The students use sign language to ask to use the bathroom. It is silent I can nod and continue teaching or working with small groups without interruption.
Part of the sign is covered up because I went from a classroom where we had our own bathroom to having to use the “big kids” bathroom.This changed the expectation.