Genitalmancy is the art of reading someone's fortune based on the size, shape, color, and assortment of their genitals. It cannot be learned and must be passed on heretitarily. It is possible that the abillity to divine is increased by covering nearby furniture in plastic wrap. There's a Genitalmancy place in New York.
In the first book both Barry and Ferd went to get their genitles read when they were in New York. In his fifth year Barry told Bumblemore that while he thought he was being a petting prat he was actually practicing Genitalmancy for his A.U.K.s (which was useless because both Barry and Bumblemore knew that you couldn't learn Genitalmancy because it's genetic).