I know how to do it with young children, say it isn't kind and we want to be kind, don't we? sort of thing.
But when they get into KS2 and secondary, if children say something unkind they do it to hurt.
So what do you say to stop them, sharpish?
EG, yesterday I passed a child I knew vaguely, taunting another about being fat. (I say taunting but I just heard the word "Fat!" as they were running about.)
There wasn't the opportunity to say anything, but what would I have said? The other child is overweight and I'd worry I'd make things worse.
If it were my child saying something like that there'd be The Long Talk when we got home. However I am talking about essentially nipping something in the bud with a well-judged reprimand. I can't think of a well-judged reprimand.
(Also must stress that I don't go about telling off other people's kids in the street. Usually. )
My gut reaction would be to sneer at the teaser: "Oh you're soooo perfect are you? Have you actually got a mirror?" Which is far too unkind.
Any teachers out there care to advise?