This is stupidly bugging me. There was a SF/F book I once read that had what I thought was a reference to my (lovely, bonkers) Hungarian step-grandfather Buci Torday. Might be coincidence, but he totally did this:

A character had one of those machines that you hang upside down on to help with a bad back, and would be found doing so at all times of day, because possibly a vampire.

But I really can’t remember what it was… Was it Pratchett? Adams? Possibly even @cstross

Anyone?