Unlike its vestibule, the vagina is derived embryologically from the primitive egg ducts which, like nearly all other internal body structures, are poorly supplied with end organs of touch. (Alfred Kinsey)
Thanks Antonio. I agree with you. Women are sexually passive due to lack of arousal. For a man, intercourse is a hugely arousing prospect. Intercourse represents men's reproductive function. Women are impregnated regardless of their responsiveness (arousal and orgasm. So for women, intercourse is simply an act of impregnation, which explains why they instinctively avoid it. Women look for an emotional connection (usually backed by a legal contract - called marriage) before they are willing to offer a man regular intercourse. Men always pay directly or indirectly to be the penetrator in sexual scenarios. The receiver obtains rewards (emotional and/or financial) for allowing the male to enjoy this pleasure from her (or his) body.