May also be used in the company of grandparents, teachers, preachers, and others who disapprove of cussing.
Does not apply to all professions. Musicians and construction workers have no need for a work mouth.
-Did you just say fuck?
-Yeah, sorry. I forgot to use my work mouth.
At a party:
-Did you just say fiddlesticks?
-Yeah, sorry. I still have my work mouth on.