"Dad, you don't say 'my bad' to ladies. You have to say something else."
"Like what. Can you give me an example?"
"Like 'Sorry, ma'am' or something princely like that. Dad, you really need to know these things, because you have a wife!"
"But it's ok. But your mother should have taught you these things."
And on and on and on. It was one of the cutest conversations I've ever had and it made for a fantastic afternoon:)