Tanit“Why? Is it only British?”
Why? Because, taking the idiom literally, your teacher's head would be missing at the end of the process! There would be a lot of blood. So unpleasant, don't you think?
Yes, that's an idiom in both American and British English. (I know exactly what you meant.) I was just making a joke by taking the idiom literally.
I'm sure you can make the same type of joke in Italian, for example, maybe with "prendere un granchio", if you just think up the right context where it works in a comical way.
CJ