In ancient Japan , the word for "having sex" meant marriage! So, having sex with someone before marriage was considered extremely immoral. This mentality has crept into today's Japanese XXX culture in an interesting way.
If Western XXX can be likened to a sunlight in an open blue sky, then Japanese XXX is definitely the opposite by being a moonlight covered by a misty cloud. This metaphor best describes the difference between Western SEX culture and its Japanese counterpart. In essence, sex in the West is definitely "out there" and more open while in Japan, sex culture is more closed and mysterious like a misty-covered moonlight.
Japanese sex culture exists in this restrained atmosphere. It is restrained desire. This special characteristic of Japan's sex culture gives it a secretive quality, and makes the Japanese naturally discreet especially when it comes to showing or talking about their sex lives to others.
For Japanese girls, it is especially embarassing to show how they truly feel while having sex. Most Japanese girls cannot easily express their feelings. Instead, they try to hide their emotions during the actual act. They mask their voice by panting and making sounds. It is up to their Japanese lovers to unleash the wild animal that truly resides within them. The man takes on the role of a strong wind that must blow away the dark and heavy mist covering the beautiful moon. If a man is truly a good lover, he can successfully unleash the wild side in her, and therefore, reveal the "moon" in her.