Men’s focus on the vagina[i] is natural given their sex drive (to impregnate a female). To experience orgasm a woman needs a lover who understands the anatomy involved in female orgasm. This includes the clitoris, the labia and the entrance to the vagina. Lesbians share the same anatomy as their lovers so they know what anatomy works and what does not.
Pornography shows women stimulating the clitoris at intermittent intervals during sex as if clitoral stimulation simply increases a woman’s arousal rather than being critical to orgasm. Such techniques do not reflect how women who are intent on orgasm stimulate themselves.
Women would have to be more sexual than men if they could orgasm with less stimulation than men need. Men stimulate their penis from beginning to end of sexual activity. Similarly a woman achieves orgasm by stimulating her clitoris from the start of sexual activity until climax.
A woman ceases stimulation once orgasm is reached. The clitoris is too sensitive for further stimulation to be pleasurable (or even comfortable). There is no reason to continue stimulation. Orgasm coincides with the sense of release and the end of our ability to be aroused by a particular fantasy. Orgasm, when it is our objective, defines the end of that activity.
Just as fantasy is used to achieve orgasm when alone, penetrative stimulation with a lover acts as a catalyst, by providing a subconscious turn-on, so that clitoral stimulation (eventually) leads to orgasm. Unfortunately the penis does not stimulate the vagina sufficiently to act in this way.
Vaginal fisting can provide arousing sensations by stretching the entrance to the vagina and the perineum. A lover should apply pressure cautiously because fisting can be uncomfortable. The experience is a little similar to when the baby’s head breaches the vagina during childbirth.
Anal intercourse (assuming both partners are amenable) can also lead to a different orgasmic experience when combined with clitoral stimulation.
None of these techniques works every time. Stimulation by a lover has to be continued for much longer (on average 10-20 minutes or more) than when a woman masturbates herself alone (on average within 4 minutes).
Stimulation techniques are much more effective when a woman is old enough (post forty five) to have an erection of the internal clitoral organ. This occurs sporadically in line with average female orgasm frequencies.
[i] The most common error which the male makes concerning female sexuality is the assumption that stimulation of the interior of the vagina is necessary to bring maximum satisfaction to the female. (p576 Kinsey 1948)
Excerpt from Women’s Sexual Behaviours & Responses (ISBN 978-0956-894717)