The Sudanese obsession with supposedly-vanishing penises is quite bizarre. I recall reading, many years ago, about a culture in southeast Asia (I believe it was one of the myriad cultural groups in Thailand) in which the most common fear among men prone to phobias was that their genitalia would retract into their bodies and kill them. This particular fear was more common than claustrophobia, acrophobia, or any of the other phobias which are more common in other cultures. The article said nothing about a popular suspicion of sorcery, though.