there’s no cliche or stereotypical image concerning a headmaster spanking a girl over his knee.
Such images may exist in the fantasy worlds of ‘spanking art’ and ‘spanking literature’ but I’ve never seen such an image or read of such an act in mainstream media (except when it related to the headmaster’s being charged with offenses relating to same).
Of course, it’s impossible to say that such a thing never happened – just as it’s impossible to say that headmasters never took girls into their offices and painted their bare bottoms bright blue. However, if such things did happen, the people concerned have all kept very quiet about it.