Even though I am currently resident in Japan, I did most of my senior schooling in the UK. I remember that at one very strict private girls school I attended the tawse was used quite often. However between tawsings the implement was stored in a special container immersed in water to keep it supple.
A few of the senior girls found out about this and decided to sneak into the senior mistresses’ office and add some clear electrolytic fluid to the water.
This had the effect of making the tawse a very good conductor of electricity. This meant any motion of the tawse through a strong magnetic field would produce an induced counter magnetic field in the tawse