1. a play on words that occurs when a person makes a pun within a pun, often followed by great excitement and a sense of accomplishment for the person who told it. this is a very powerful pun.
2. an extended pun, not limited by frequency of occurrence
person 1: i was banging my girlfriend so hard during titanic, i missed the ending. what happened?
person 2: loose lips sink ships.
person 1: dude, that was a double pun. touche.