This sign is posted in a bathroom stall at work, encouraging people to sit on the toilet, and not treat it like a “squaty potty.”
I’ve seen it before in Asia; it appears often in China, for example, where many bathrooms have stalls with squat toilets as well as stalls with “foreign” toilets. I guess some “country people” (their words, not mine) have never seen a western style toilet, and so treat it like a squat toilet.
That behavior apparently rubs some people the wrong way here in Vietnam. The sign in the bathroom stall was annotated with some additional information: