It doesn't mean anything. It expresses the speaker's contempt for something. I don't understand the scene depicted, so can't help further. (I think it's a particularly Jewish form of wordplay - but maybe just because I remember the punchline of a joke - not the joke itself - set on the road to Damascus: 'Paul Schmaul; my name's Saul already.')
Eh, I probably haven't described it very well. That scene is from a book of fantasy, Thomas saw another face of the hostess, but the others couldn't; he thought it was merely a mask that she wore, and considered it a superb joke, whereas his girlfriend saw only the hostess bring in a pie for dessert, hence the admonishment.
Anyway, I get the idea. I always find word play peticularly difficult. Thanks a lot!