Concerning a child’s use of good manners
Mind your manners.
Mind your Ps and Qs. (idiomatic)
I expect you to be on your best behavior.
Act like a lady.
Act like a gentleman.
Say “excuse me.”
Say “thank you.”
Say “you’re welcome.”
What’s the magic word?
the magic word = the word please
What do you say?
= Say “Yes, sir; Yes, ma’am; or Yes, please.”
(Always) remember to say please and thank you.