When I was in fourth grade, a rumor went around that "bike" was a French word for "penis." This probably came from the "bike cup" that one buys in sporting goods stores. For several months, saying someone "just got a new bike" or telling them to "grab your bike" could get a laugh out of any of us. Was this just a local thing?
I know of several other things like this, in which a random word is said to be French (or simply code) for something sexual - the famous example all over the Des Moines Metro Area was that "shut up" meant "meet me in bed in five minutes." This was hilarious to fifth graders and groan-inducing to middle schoolers.