One of the Discworld books mentions a Phrenologist's assistant.
The Phrenologist tells your fortune based on the lumps and bumps on your head, while his assistant will - for a price - put bumps in stategic places on your head with a mallet so that the Phrenologist will be come up with the sort of reading you would like to have.
Can anyone tell the name of the book that includes this character - and if possible his name. I've looked everywhere, but I simply can't find any reference and it's driving me nuts!!!