The Whorewhats School for Sexual Witchcraft was a very specialist educational establishment for those young witches born with a pure Succubus talent.
We see above their unique ‘wand choosing’ ceremony. Once the right wand was found and inserted, it would keep its witch in a state of constant arousal, but completely prevent climax no matter how hard she tried. Thereby maintaining the highest possible levels of sexual power for use in spells.
The girls were of course allowed to take the wands out during school holidays.
None of them did.