I went to a Catholic parochial school from halfway through 4th grade to almost the end of 7th. My parents were C of E, but we lived out in the boonies and the Catholic school was within walking distance (barely) (down a logging road) and getting to the public school was a pain, requiring transfers from bus to bus and a VERY early start. Turned out that, poor as we were at that time, it was worth the $10 a month tuition to avoid that daily hassle.
For 5th and 6th grades, I was in a combined class taught by Sister Mary Mercy.
Sister Mary Mercy had passed her sell-by date a long time ago. Looking back, she was probably menopausal and questioning the value of her life. Trapped daily in a class that contained a fair sized herd of unruly boys (George Carlin's stories of parochial school come to mind), with her only refuge being prayer, she tended to go from Sweet Nun to Raving Lunatic at the drop of a hat. She could peg a kid in the back row with a blackboard eraser or a piece of chalk or a Missal with unerring accuracy.
But I was One of the Good Kids. Oh, sure, I used to hide a library book in the bathroom and excuse myself when class got boring (they probably thought I needed porridge), but that was the extent of my rebellion.
So, one day (late in the day), she wrote the formulae for calculating the area and perimeter of a rectangle on the board, and she labelled them backwards. Ever the helpful child, I pointed that out.
THWACK! The yardstick came down on my shoulders, and THWACK again! Damn thing broke the second time. Sister Mary Mercy ran out of the room, ululating sadly.
About ten minutes later (I was ululating a bit sadly myself by then), Sister Mary Olive came in (she was the Sister Superior...I guess we didn't rate a Mother) and we spent the rest of the day on our knees, praying for our sins. Fortunately, it was last period.
I don't remember telling my parents about the incident...if I did, they probably pointed out that correcting one's teacher was never a good idea, no matter how wrong she was...because, back then, it was OK for school officials to hit children. It was usually done in a more organized manner, with a strap, on the hand, but whatever.
That was the only time I was physically punished in school.