I seem to remember that Chief Justice William O. Douglas of the US Supreme Court had something to do with composing this song. Here's the reference from Wikipedia:

The Erotic Muse: American Bawdy Songs says that sometime in the early 1930s, according to his autobiography, Go East, Young Man (pp. 171-72), William O. Douglas and fellow Yale law school professor Thurman Arnold were riding the New Haven Railroad and were inspired by a sign in the toilet. "Thurman and I got the idea of putting these memorable words to music, and Thurman quickly came up with the musical refrain from Humoresque."

Cheerily,
Charley Noble