Danish

There are some weird expressions in Danish, like “tisse af” (=to pee). Instead of using simply “tisse”, especially the kindergarten and primary school teachers always tell children to “tisse af”. As far as I know, you can practically only pee in one direction; where does the “af” come from?

Some Danish teachers must have been on educational trip to England, where they heard teachers telling the children “Piss off”. Proving that they had learned something, and didn't waste tax payers' money, these teachers now tell Danish kids to “Tis af”.