When my mother tanned me with ‘the slipper’, it was actually an old, large tennis shoe of my father’s, with a thick rubber sole, kept for the purpose in my wardrobe.
She always used her full weight, with the strength of her tennis-trained arm, in applying each stroke.
Each was given as hard as she could, while the severity of the tanning was varied by the number of belts given.
If Mother had determined that I needed a hiding, her punishments were never minor affairs – the slippering was always a serious punishment, never a few whacks for show, but always at least a dozen and usually more.