Essentially, a dick festival.
The Kanamara Matsuri is held each first Sunday of April at the Kanayama shrine in Kawasaki. After the lighting of the sacred flame at the shrine, a huge pink phallus-shaped mikoshi altar is carried around the city during a procession. The penis is the central theme of the whole thing (natch) and is celebrated through drawings, confectionary, bunting and other such fun decorations, and vegetable carvings.
Important to note: “There is also a museum near the shrine with a cast-iron sculpture of a vagina and a pair of legs. Visitors can purchase small penis-shaped souvenirs and rub it on the sculpture for good luck.”
Used as a fundraiser for HIV research, the festival, apparently the Kanamara Matsuri was originally centered around a local penis-venerating shrine once popular among prostitutes who wished to pray for protection from sexually transmitted diseases. It is said that there are also divine protections for business prosperity, easy delivery, and marriage harmony.
So that’s that then.