It's like how apparently "shag" is the equivalent of "fuck" in the UK, but in the US it typically refers to a type of carpet.

In fact, I only heard it in Monty Python and thought it was just another funny English word like "codswallop" or "git" or "odds bodkins" (the last of which was so bizarrely English that I didn't even attempt to understand what it was supposed to mean). It wasn't until I got to law school that the word came up during a Constitutional Law discussion of sodomy laws (which at the time were still legal - this was 1997 and I was 22).