(4) The frequency of replenishing essence, brain and sperm. The ancients believed that excessive discharge of essence would lead to the loss of essence and even human body failure, which would lead to the loss of life and life. Long-term inhibition of ejaculation will lead to long carbuncle, so it is necessary to master the appropriate ejaculation frequency. It is mentioned in Qian Jin Fang that when a man is 20 years old, he will ejaculate every four days; At the age of 30, he will ejaculate every eight days; At the age of 40, he will ejaculate every 16 days; At the age of 50, he will ejaculate once a month; At the age of 60, you should close the fine pass to avoid excessive ejaculation; If he is still strong, he can ejaculate once a month when he is 60 years old. The statement about ejaculation frequency in Qian Jin Fang is normal. People's physique is strong and weak, their age is old and strong, their essence is ups and downs, and the frequency of ejaculation is different, which varies from person to person and cannot be misunderstood. For the elderly after the age of 60, if there is no normal sexual outlet, abstinence for a period of time (two or three months) may lead to the loss of erectile function, so the elderly should not abstain from sex. The general principle of sexual intercourse set forth in The Art of Sexual intercourse is to vent less and cherish essence, so that you can be full of spirit, feel comfortable, energetic, light and energetic. Besides, many books in the room have discussed the guiding method of "replenishing essence and brain". Specifically, when you want to ejaculate, press the perineum behind the scrotum and in front of the anus with the middle finger and the twelfth finger of your left hand. The penis is also tied and motionless, and it will vent when it opens its mouth, and it will not hold its breath after pecking dozens of times with its upper and lower teeth. In this way, semen will not be ejected, and brain marrow can be supplemented. Because essence is the foundation of life, and brain is the palace of god, it can make people feel refreshed, radiant and immortal. This view was put forward in ancient times, limited by the level of scientific development at that time and driven by the psychology of seeking longevity. Obviously, this does not conform to the viewpoint of modern science. (5) Immobilize semen, prolong life and prevent diseases and diseases. Ancient sexology not only attached importance to the indoor training of strengthening the body, but also favored the medicine stone to strengthen the body and strengthen the yang. For example, Qian Jinfang said: People over 40 years old should always take tonics, so as to be a hundred times stronger, and the more sick they are, the longer they will live. Medical stone can promote sexual function, help pregnancy and prevent diseases. Many books can be found in the room, such as Poria powder in Women's Classic, which shows that it can preserve health and prolong life. The prescription is Poria, stalactites, mica powder, Dendrobium, Acorus calamus, Semen Platycladi, Semen Cuscutae, Radix Dipsaci, Radix Asparagi, Eucommiae Cortex, Achyranthis Radix, Fructus Schisandrae Chinensis, Alismatis Rhizoma, Cortex et Radix Polygalae, Flos Chrysanthemi, Fructus Cnidii and Cortex et Radix Polygalae. For example, Cistanche deserticola Pills and Polygalae Pills in "Jade House Secrets" can all strengthen yang. Other prescriptions, such as promoting sexual desire, treating short penis, treating pain during sexual intercourse, and helping pregnancy, are scattered in books and medical books in the room. In addition, many contents of ancient sexology, such as mate selection criteria and sexual taboos, are limited by space, so I won't repeat them here. In a word, ancient sexology has a wide range of subjects, but it is nothing more than preserving health and preventing diseases, prolonging life and reproducing children and grandchildren. But some of these concepts need to be treated with historical materialism.