If you want to get even more confused, until last year, I was living in a prefecture famous for its penis festival.
OT, C'mon Japan! You do have a special time once a year in which several parts of the country parade a massive carved wooden cock, a massive vagina, and/or several smaller ones, and sells dick themed souvenirs, keychains, and candy. You can't tell me in all honesty that this is too much for the children. The same children encouraged to dress up for and come to these festivals.
EDIT: Thought maybe I should add a link. feel free to browse at your own peril.
That being said, if you've never seen a penis on the internet... How?
http://photoguide.jp/pix/thumbnails.php?album=529