Women are, according to the wisdom of Aristotle, imperfect, flawed men that failed to develop their man-parts properly when in the womb, and so instead got a hoo-ha. They are incredibly lustful as a result, because they long to be filled with man's seed in order to feel the wholeness that comes from having man-parts instead of a hoo-ha. They are only happy when pregnant or actively having sex, which is why all women are either mothers or prositutes. Their sexual response is entirely unimportant, because their sole purpose is to be a recepticle for man's seed to bear more men (not, gods forbid, more women), and so no man ever bothered to study it in any great detail--barring Tiresias, but we all know how that turned out.
Something to do with water, secretions, yada yada yada, not important unless they make babies.
Women, when aroused, have a strong desire to have babies, which completely governs their sexual drive. They seek after men who would be good at providing them babies so they can have sex with them. However, since they are always imperfect without a baby or seed inside of them, they are always aroused, and thus always want babies, and therefore sex. QED.