The process of sexual physiological response can be divided into sexual excitement period, plateau period, climax period, and decompensation period. The specific sexual physiological responses of men and women are also different. The signs of entering the excitement of sexual response are erection of the penis in men and increased secretion of the vulvar vestibular gland and vaginal slipperiness in women. The time to arouse sexual excitement differs between men and women, men can reach sexual excitement in a few seconds, while women need to be effectively stimulated for 10 to 30 seconds before they become sexually excited, into the excitement period, both sides will show mental pleasure and excitement. 2. Platform period: Platform period, also known as the duration, is the stage of steady development of sexual tension after excitement to orgasm, lasting about half a minute to a few minutes. Compared with the excitement period, the platform period does not have the typical physiological changes, but only the continuation or intensification of excitement. 3. climax period: climax period is the shortest, a few seconds and passed. In the climax both men and women release the previously formed muscle tension through spasms of the involuntary muscles, and at the same time experience an indescribable pleasure. The climax of the sexual response is characterized by the ejaculation of the man. The female orgasm is not as indicative of ejaculation as the male, but is mainly characterized by a rhythmic contraction of the lower 1/3 of the vaginal muscles, which is initially strong and powerful, and then decreases in intensity, with a prolonged interval between contractions and a marked increase in secretions, usually lasting for a few seconds or a dozen seconds. At the same time, the hyperventilation that occurs in men during orgasm is a normal phenomenon, and the respiratory rate, heart rate, and blood pressure will continue to rise. Others, such as moaning during orgasm, are not random in women, but not in men, and it is a deliberate expression of pleasure. 4. fading period: fading period refers to the body muscle tension is relaxed, sexual energy is released, the process of congestion and swelling gradually subsided, generally need 5 to 10 minutes. After the climax of sex, men’s libido quickly faded, into the period of inactivity, the length of the period varies from person to person. And women’s libido is slower to decline, is gradually fading for up to several hours, when women do not feel tired, eager to further embrace, touch, so that their relaxed body and mind to get the maximum satisfaction, if men do not know or ignore this need of women, and fall back to sleep, often bring trouble and anxiety to women, but if at this time in the sexual stimulation, women are easy to get orgasm again. References: Yao Shuqiao,Yang Yanchun. Medical Psychology. 6th edition [M]. Beijing. People’s Health Publishing House,2013.