My PE teachers used the sole of a Converse tennis shoe. One kept a bucket full of paddles in various shapes and sizes, one of which was a 1-inch thick middle of a baseball bat. Me and some other kid got caught talking in health when class the coach stepped into the hallway for a bit. When he came there were just yakking it up.
Coach pulled the bucket out of the closet and made us choose our poison. I took the smallest thinking that wouldn’t hurt as much and the other kid took the sawn baseball bat. I grabbed my ankles and got my swat first and he smacked my ass hard and left a huge welt. Then when he went to the other kid who was bent over at the ready when Coach stepped up to his backside like Reggie Jackson waiting on 3-0 pitch and swang with all his might. But just when he was about to make contact he checked his swing and then just lightly tapped him!
Had a tennis friend who was a high school principal. It was his job to paddle offending students.
He told me one time as the paddle was getting ready to strike, the student put up his arm to protect himself and the paddle struck his arm, breaking it.