On the subject of girls crying during slipperings, a lot depended on the circumstances. Girls slippered in front of the class would be less likely to cry for the reasons suggested in Declan’s opening post and because such punishments were usually, though not always, less severe and were generally carried out more quickly unless the teacher had a liking for long pre-punishment rituals.
A slippering in front of the class could be a very brief event. Something like: “You! Why are you talking? Come here. Turn around, bend over.”
Whack! Whack!
“Right, back to your seat.”
If the teacher was one of those who liked to slipper pupils at their own desks, it could be even quicker. It would be over before they knew it, so they often wouldn’t have time for whatever part of the brain it is that causes crying to get into gear.