How old were you at the time? Your account highlights so succinctly just how casual corporal punishment could be in those days. I have a story so similar it could be plagiarised! We were waiting for one of our 'softie' teachers to turn up for the lesson - she never could say boo to a goose, so we didn't care. But she must have been away that day because the school martinet turned up. Probably more than half the class were actually at their desks, but a group of us - around 10 - were gathered around desk at the back of the room having hysterics over something. Like you, we were called out, and in front of the rest of the class, we each had to touch our toes for six real hard ones with the size 100 (or so it felt) plimsoll.
My point is that we just treated it as a normal part of school life. No parents came charging to the school to complain. In fact none of us would have been stupid enough to tell our parents - given the strong probability of a repeat dose at home.