I went to an all boy’s English grammar school in the late 50s and early 60s. The attitude to corporal punishment was part and parcel of the very male, macho culture of the school in all sorts of ways.
The slipper was used frequently by prefects and masters. So it was quite common to watch another boy being slippered. From the point of view of a spectator we admired a good thrashing in the same way that men admire a good sporting performance. A strong athletic swing of the arm elicited the same respect as a cricketer hitting a ball for six. The sound of the plimsoll striking trousers stretched over a boy’s bottom was enjoyed all the more for its loudness and crispness. .