Coitus means sexual intercourse, the purpose of which is procreation, reproduction and enhancement of affection, and requires attention to hygiene and frequency of sexual intercourse, and should not be used during menstruation, early pregnancy and other times. Intercourse means sexual intercourse, which is the process of rubbing the penis against the vagina while it is in an erect state. Usually, sexual intercourse is for reproduction, reproduction of offspring, but also can enhance the relationship, pleasure enjoyment, to a certain extent, is conducive to physical and mental health, relieve stress, maintain a happy mood. In addition, the two sides must pay attention to the hygiene of sexual intercourse, women use warm water to wash the vulva, men need to wash the penis and glans, so as to avoid the process of coitus will bring pathogenic bacteria into the vagina, resulting in women suffering from gynecological diseases. Secondly, but also pay attention to the frequency of sexual intercourse, if after sexual intercourse appeared tired, waist and knee soreness and other symptoms, it means that excessive sexual intercourse. Generally in the menstrual period, early pregnancy and late pregnancy when you can not cohabit, to prevent adverse effects on the body. To summarize, sexual intercourse need to pay attention to safety, pay more attention to rest, avoid overwork.