@Diest TKO,
Actually, I have used the opposite psychology.
My twin nephews lived with me for a few months when they were 5. They had a problem with swearing.
So I told them they could say anything as long as they didn't use the "really bad word"-- which one day I accidentally slipped was "quap".
This worked like a charm (the other words lost their luster real quick).
((maybe this school isn't so stupid after all))