A friend of mine was slippered at home, but her mother was a schoolteacher – so that probably explained it.
My Dad used a rubber-soled carpet slipper on my bare bum and I also got the slipper at school.
I always feared the slipper more than the cane when I was at school. What was refered to as the slipper was in fact a size 11 plimsoll with a rubber sole which was invariably administered to a backside protected only by a thin pair of shorts. Also the PE teacher who inflicted the punishment was extremely fit and would deliver each whack as hard as he could.