If men were attracted to responsive women, presumably they would hope for a woman who could orgasm within say 5 seconds of being stimulated. In reality, a man needs a woman to offer intercourse for as long as he takes to ejaculate (no more no less). But a woman has no control whatsoever over how long the stimulation she obtains from intercourse will last for.
Some women show off by talking about sex (naturally they mean intercourse) as if they need it as much as a man does. It’s as if a woman orgasms every time a man offers her an erection but at no other time. [i] Try asking women what turns them on and they haven’t a clue! Women typically suggest an assortment of possibilities, most of which are not remotely erotic. It is clear that women expect only emotional sensations from intercourse.
Sexual arousal starts as a subconscious response to eroticism in the brain. We become conscious of arousal because this trigger increases the flow of blood into the pelvic area. In turn this increased blood flow causes the genitals to become more sensitive to stimulation. For men this increase in sensitivity is very significant. But a woman is typically unaware of arousal.
In men the increase in blood flow causes a significant stiffening of the genital structures (particularly the penis). In younger women there is little discernible swelling of the genital structures but in older women (over the age of forty) there can be some noticeable swelling around the labia indicating tumescence (but not rigidity as in the male) of the clitoral organ. This increase in sensitivity of the penis or clitoris when combined with a mental focus on eroticism (either the innate eroticism of the sexual activity or imagined scenarios) enables a person to stimulate themselves to orgasm.
Muscular tensions in the pelvic region increase, culminating in a peak that is suddenly dissipated (providing a sense of release). Orgasm involves the sporadic contractions of the muscles, sensations of ejaculation of semen (men only as there is no equivalent female sensation) and the sensation of the extra blood (accumulated in the genitals) flowing away from the area.
Young women are unaware of clitoral tumescence. Nevertheless the sensations of arousal and orgasm are identical to older women who experience this physical phenomenon. So women masturbate to orgasm with similar frequencies throughout their lives until menopause. But their responsiveness with a lover only develops in middle age (if at all). The main benefit of clitoral tumescence is an increased sensitivity in the pelvic area during sexual activity with a lover, who provides the correct internal stimulation.
[i] Nearly all (but not all) younger males are aroused to the point of erection many times per week, and many of them may respond to the point of erection several times per day. Many females may go for days and weeks and months without ever being stimulated unless they have actual physical contact with a sexual partner. (Alfred Kinsey)
Excerpt from Sexuality & Sexual Techniques (ISBN 978-0956-894724)