Orgasm is the physiological response which brings sexual intercourse to its natural and beautiful termination. It is preceded by a very dramatic increase in all of the phenomena noted above. In the moment just preceding orgasm, muscular tension suddenly rises to the point where, if the sexual instinct were not in operation, it would become physically unendurable. The pelvic motions of the man and the movement of the penis back and forth within the vagina increase in speed and in intensity of thrust. The woman’s pelvic movements also increase, and her whole body attempts with every move to heighten the exquisite sensations she is experiencing within her vagina. According to many women with whom I have discussed this experience, the greatest pleasure is caused by the sensation of fullness within the vagina and the pressure and friction upon its posterior surface. At the moment of greatest muscular tension all sensations seem to take one further rise upward. The woman tenses beyond the point where, it seems, it would be possible to maintain such tension for a moment longer. And indeed it is not possible, and now her whole body suddenly plunges into a series of muscular spasms. These spasms take place within the vagina itself, shaking the body with waves of pleasure. They are felt simultaneously throughout the body: in the torso, face, arms, and legs--down to the very soles of the feet. These spasms, which shake the entire body and converge upon the vagina, represent and define true orgasm. At this moment the woman’s head is thrown back and her pelvis tips upward in an attempt to obtain as much penetration from the penis as is possible. The spasms continue for several seconds in most women, though the time varies with every individual, and in some women they may continue though with decreasing intensity, for a minute or even more. Many women can repeat this performance two or more times before their partner has his orgasm. The pathway, neurologically and psychologically, has been set for orgasm and, if her partner continues she can respond. I have had women report that the last orgasm is sometimes more intense and satisfying than the first. If the woman is satisfied by her orgasmic experience she will discharge the neurological and muscular tension developed in the sexual build-up. When satisfaction has been achieved, her strenuous movements cease and within a short period blood pressure, pulse, glandular secretion, muscular tension, and all the other gross physical changes which characterize sexual excitement return to normal, or even to subnormal, limits.