Sometimes a phallic symbol represents fertility, other times, not.
Every spring the Japanese city of Komaki is home to a shindig called Hounen Matsuri. Residents swear up and down that Hounen Matsuri (aka the Penis Festival) has more to do with spring and fertility than the male reproductive junk, but according to AlterNet, many people think it's a crotch party:
On the surface, it seems like an excuse for old Japanese guys to fill themselves with cheap beer and chase girls around with bananas. Also, the predominance of the phallus throughout the shrine's decor is startling to say the least.
They go on to explain that the event has religious significance: a local nobleman's daughter from 1500 years ago is revered at her shrine and presented with a 6-foot plus gym-dandy. The town is littered with phallic symbols and sake flows like wine, somewhat obscuring the festival's true meaning. Despite Hounen Matsuri's significance, you'd guess that many of the attendees are drawn to the debauchery and the plethora of phalluses. (I haven't seen this many wangs since I opened a Chinese phone book… thank you, I'll be here all week.) It's sort of like how Mardi Gras is a celebration of the rebirth of Jesus but also a time for exposing ourselves, riding on a floats and drinking the occasional Hurricane from Pat O'Brien's. For real, this sounds like a great spot for a bachelorette party. Read: Love In Japan Keeps Getting Weirder
Speaking of Japanese penis festivals, Gather.com has the word on an event called the Kanamara Matsuri ("Matsuri" meaning "festival" and "Kanamara" loosely translating to "steel phallus") in Kawasaki (oddly, not home to Kawasaki motor vehicles). While the event references a "steel phallus," the show is actually dominated by a giant, pink penis. This year's parade broke all sorts of records in terms of attendance and probably d*ck jokes. These worshippers would make Frank "TJ" Mackey shed a tear in pride.
In summary, sometimes a penis is more than just a penis, and in other cases Japanese people seem to be pretty obsessed with the male genitalia. Plan to attend next year's Hounen Matsuri? Bring your booze shoes and don't mind the overwhelming preponderance of cyclopses staring right atcha.