Codswallop?

A friend of mine gave me a stack of flashcards of funny english terms/phrases.

One was Codswallop, which means garbage or nonsense, as in 'that's a lot of codswallop!'

Another: "her majesty's pleasure" = doing time in prison

"Yonks" = ages

"splash out" = spend a lot of $

and my personal fave:

"spend a penny", one of many funny phrases for using the toilet;)

The joke will be on me if I'm throwing these terms around and they're....wrong!
I'd be embarrassed for yonks.