Debussy as term for bathroom?

In Michael Bishop's SF book Transfigurations (1979), the author (in the course of the narration by the main character) refers in several instances to one or another "debussy", by which he evidently means a bathroom (i.e. a loo/WC/toilet/washroom, depending on your local usage).

I've never encountered this elsewhere and searching has turned up nothing. Is this an invented usage of the author's, or is there some precedent somewhere?

"Debussy" is a phonetic representation of pronouncing "WC," not to be mistaken for the classical composer Claude Debussy. Basically, the author's employing an eye dialect to show how the character pronounces--or mispronounces--the letter W (double u) in WC.