The Kanamara Matsuri (Festival of the Steel Phallus) is an annual Shinto fertility festival held in Kawasaki, Japan in spring. The exact dates vary: the main festivities fall on the first Sunday in April. The penis forms the central theme of the event that's reflected everywhere; in illustrations, candy, carved vegetables, decoration, a parade of mikoshis, etc.
The Kanamara Matsuri is centered around a local penis-venerating shrine, once popular among prostitutes who wished to pray for protection against sexually transmitted diseases. It is said that there are divine protections also in business prosperity and the clan's prosperity, easy delivery, marriage, and married couple harmony, etc. Today, the festival is used to raise money for HIV research. There's also a legend of a demon that hid inside a young girl and castrated two young men on their wedding nights before a blacksmith fashioned an iron phallus that was used to break the demon's teeth, leading to the enshrinement of the item.