I finally found the offending word, it's totally innocent, but if you remove one or two letters it means something completely different which isn't innocent!
That is a very good fantasy idea, like that the junior teacher gets her punishment hard enough to mean she as to stand for the rest of the day, which will please her students I am sure. Would make a good fantasy story.
Or a junior teacher on teaching practice being wound up by the pupils. When one forgets to do her homework the others insist the normal punishment is to be slippered, and one of them hands over her plimsoll for the task. The student orders the girl to bend over and delivers quite a hard slippering considering it's her first attempt. Over the next couple of weeks she becomes expert at slippering her pupils. Then one day the Head catches her with two pupils bending, over skirts up, he allows her to complete the punishment then takes her into the corridor. To the delight of the class they hear their teacher receiving a thorough bare bottom thrashing and there are smirks when she returns to the room, teary eyed, and decides to stand for the rest of the lesson.
That is a good idea also, and good that she goes harder than she maybe should with not really knowing how to administer a slippering. And with it being in front of the class adds to her humiliation which is good, makes for a good fantasy.