The only teacher that I recall in the changing rooms was Mick. I don't think that he carried a strap ...so did he use the inside of his hand to slap you or was it someone else. I didn't have a problem with discipline if there was a reason for it. In Latin I saw a teacher strap a boy because he got a verb wrong which is I think inappropiate behaviour for a teacher. For not trying maybe but for making a mistake then that is inappropiate. However we lived in different times. Such times as when the b...specials raided the school looking for a 16yr old student. The boy was a boarder and went over the back wall.
I had left my gym gear at home. I was given a set of sheets that had to be filled in for the annual athletics carnival. The teacher left the changing rooms for about 15 minutes. When he returned, he found that I had filled in the sheets incorrectly. He lifted his hand and walloped me.
On another occasion, a teacher was dictating to us. My bag was sitting on the desk in front of me. The teacher apparently (and wrongly) assumed that I was hiding behind the bag and wasn't taking down the dictation. Suddenly the bag was whipped away. I looked up to see his fist coming through the air. He caught me directly on the eye. That rendered me useless for the rest of the lesson, because I couldn't open the eye.
The last incident I recall was in a Latin class. The teacher had gone to the end of the row to do something. Naturally, we all looked around at what was happening. As he walked back up the row, he hit me on the head with his opened hand because I wasn't facing the front.
None of these had anything to do with discipline, and none warranted the treatment that was dished out. However, as I said earlier, my experience of St Malachy's was that physical punishment was just a way of life, and positive reinforcement was almost non-existent.