I think that Dominum makes a good point about the warning element of a non-painful slippering, but this warning element had certainly lost its value for one female teacher I remember, who lightly slippered a pupil or two almost every lesson. I can only conclude that she enjoyed it, as did some of the pupils who would provoke her just to get it.
Gordon, if you were the only child to be punished in this ritualised fashion, then I would see that as a warning to the rest of the class. If however, it happened regularly to other children, then I am sure that the woman had a spanking fetish.