Thing is, I can remind my kids of their embarrassing sayings as toddlers...always said in public at full volume: DD aged about 4 at supermarket checkout was pondering whether all men were anatomically similar to her bother (then 5 and a half). It went something like this "does Daddy have a willy, does grandad have a willy Does THAT man have a willy? "
Now that they're teenagers it's just too easy to embarrass them, no challenge at all.
Jude xx