Batman: "I don't know, but whatever it is, it can't be good, that's for sure!"

Batman: "There's only one thing to do - we've got to get to the Joker before he can get to us. Let's continue our study of the great boners of all time - and try to guess the Joker's next move..."

That and more at this collection of unintentional(?) innuendo in old comics.

Also, I found a skull!