My DS (aged 5) has a little American friend who has taught him the word "butthead" (they are in the same class). They are very good friends and say butthead to eachother, laugh and run away. Very good natured. I thought that the word was not really rude so I didn't have a problem with it and besides, they were in no way teasing eachother or intending to cause upset.
My DS has today got into trouble at school with his teacher over this word. So I would like to know, how rude is this word in America? Is it awful for a 5yo to say it? Could you give a British word that is equivalently rude?
Just to add that I don't allow my DS to swear (eg shit) and he doesn't swear. I am feeling a bit like the teacher thinks I am a terrible parent!