As you know, Bob, the mouth is the buccal cavity.

While I feel no particular need to say "Smile! It might never happen!" to the weary or distracted or depressed, some people do. It is regrettably not legal (in most jurisdictions) to strike such speakers about the head and shoulders with a full teapot. So I can only urge these tediously cheerful people to vary their equally tedious repertoire with "Buccal up!"

...sorry.