5yo son says it when he's being told off. I suspect it because its word we avoid as much as possible (as in 'er, BusyChild, we don't call each other stupid in this house'), and I think he uses it to divert the bollocking. He's quite an emotionally intelligent manipulative kid.
I want to correct it, because he's not stupid. But I don't want to be diverted by him either.
Any thoughts on what I can say?