Another issue with my 2 boys.?

Chance are, they're saying it to get a rise out of you. I would ignore them when they say it. If they've discovered it doesn't get to you, they'll probably stop saying it. I would probably punish them if they do it in front of your guests (because that shows no respect for guests), but if they happen to do it when it's just you around the house, I'd ignore them.