There's an immediate analogy right there in the word "lips" between the vagina and the mouth. Interestingly, according to French anthropologist Jean Malaurie, Eskimos have extremely quiet sex.
One of them suggests that only 32 percent of women give fellatio out of pleasure; the remaining roughly two-thirds do it as an obligation. The passive one -- usually a woman or a slave -- was the one giving fellatio or, to understand it more clearly, the one receiving the penis.
What about countries where women have few -- or less -- social liberties than contemporary Western women do? There's not much difference here between the two cultures. I'm not a psychoanalyst, so I don't want to make any sweeping commentary here.
Clearly even the most rigorous bout of coitus pales in comparison with the intimacy of fellatio, at least for the one giving it: Ads are currently disabled. Pornographic cinema is an American business.