Droit de seigneur
Droit de Seigneur... Whatever that is, no one is ever prepared to explain but it was definitely something a feudal lord ought to have. In Lancre some imagined it was a kind of large hairy dog which needed a lot of exercise.
In Ankh-Morpork, exercising one's large hairy dog, on the part of a certain nobleman, ultimately resulted in Slope Nobbs, grandfather of Nobby Nobbs, who very briefly took the ermine, when it was offered. One should take great care when exercising one's hairy beast.
Definitely not to be confused with droit de mortis, the now almost moribund practice of enhancing one's promotion prospects at Unseen University by offering a terminal retirement package to the senior wizard whose pointy shoes you want to fill.