DS is 5. He loves mischief of all forms. Hiding from people, playing tricks/jokes, singing songs with the words wrong etc. It's mostly harmless as we've really turned a corner with actual bad behaviour. But some of it is still clearly unacceptable at school. At home I mainly ignore it or just roll my eyes, but School are not happy as i think it can be pretty disruptive. I tried talking to him about it tonight as he's been very honest; he just gets a thrill from it and enjoys it. How do I convey that it's wrong without crushing his spirit?