<a href="http://www.livestrong.com/article/12473-orgasm-phases/" target=_blank>Orgasm</a> is the point at which all sexual tension is suddenly released in a series of involuntary and pleasurable muscular contractions that may be felt in the <a href="http://www.livestrong.com/article/12495-the-vagina/" target=_blank>vagina</a> and/or uterus (although some women experience orgasms without contractions). Orgasm is reached through copulation or <a href="http://www.livestrong.com/article/12461-masturbation/" target=_blank>masturbation</a>.
During orgasm the body stiffens and the muscles contract. Involuntary muscle contractions and spasms may occur in various parts of the body, including your legs, stomach, arms, and back. The muscles of the vagina relax and contract rapidly, as do the muscles of the uterus. The glands of the vagina discharge a <a href="http://www.livestrong.com/article/12463-female-ejaculation/" target=_blank>watery secretion</a>, which acts to lubricate the vagina.
The main physical changes that occur during a sexual experience are a result of vasocongestion. This is the accumulation of blood in various parts of the body. Muscular tension increases and other changes occur throughout your body also.
Many women have multiple orgasms. Masters and Johnson documented this occurrence more than 25 years ago. Theories suggest that muscular contractions associated with orgasms pull sperm from the vagina to the cervix, where it's in a better position to reach the egg. Researchers believe that if a woman climaxes up until 45 minutes after her lover ejaculates, she will retain significantly more sperm than she does after non-orgasmic sex.
The difference between a "clitoral" and a "vaginal" orgasm has to do with where you are being <i>stimulated</i> to achieve orgasm, not where you <i>feel</i> the orgasm. The clitoris has a central role in elevating feelings of sexual tension. During sexual excitement, the clitoris swells and changes position. The blood vessels through the whole pelvic area also swell, causing engorgement and creating a feeling of fullness and sexual sensitivity. Your inner vaginal lips swell and change shape. Your vagina balloons upward, and your uterus shifts position in your pelvis.
For some women, the outer third of their vagina and the cervix are also very sensitive, sometimes even more sensitive than the clitoris. When the <a href="http://www.livestrong.com/article/12451-gspot/" target=_blank>G-Spot</a> is stimulated during intercourse or other vaginal penetration, these women do have intense orgasms. This would be what is referred to as a vaginal orgasm -- without clitoral stimulation.
<i>For information on how to masturbate, click <a href="http://www.livestrong.com/article/12490-how-to-masturbate-a-guide-for-women/" target=_blank>here</a>.
To find out more about the male orgasm, click <a href="http://www.livestrong.com/article/12496-male-orgasm/" target=_blank>here</a>.