Actually I'm with samurai8.

And it all because:
1. School teaches it them at age about 12 years old.
2. Their older friends telling them about it.
3. Because of the internet (ads and such things).

Once in TheJapanChannel in youtube, he told that girls are not so open to other guys, but in the comments one person said that they make it every time and everywhere...
I think that now Japanese girls are slowly being attracted to the "love" world, which I don't really like...
But do I hope that I'm wrong...

Does anyone knows the real answer? Does Japanese girls now are really attracted to sex? Or there are still some girls who didn't lost their minds (And I mean if more than 80% girls) which I hope for!