Preparation for sex: Which parts need to be washed? (Adult novel about sex knowledge)

The final preparation before sex is pre-sexual hygiene. Some people find it troublesome and are unwilling to perform pre-sexual hygiene work, which is very inappropriate.
Both men and women must brush their teeth, because unpleasant odors coming out of the mouth will not only make the kiss unpleasant, but also may make the other party give up the desire to have sexual intercourse.
Both men and women must keep their reproductive organs clean, especially during sexual intercourse, and pay more attention to hygiene issues.
The penis is the male's mating organ and must be cleaned before sexual intercourse. Prevent bacteria from entering the female vagina and causing women to suffer from gynecological diseases. There is often some dirt accumulated between the foreskin and glans of the penis. This dirt must be cleaned, and the inner skin must be turned over and cleaned.
The female vulva has many wrinkles, sweat glands, sebaceous glands and vaginal secretions often accumulate in the wrinkles, and the vagina is located between the urethra and the anus, making it very susceptible to infection. Therefore, the reproductive organs must be cleaned before sexual intercourse, otherwise, it is easy for bacteria to enter the vagina and cause infection during sexual intercourse.
Among patients with sexually transmitted diseases, there are some couples whose spouses have no history of promiscuous sex. Before becoming ill, they had never been to the hospital for treatment, so medical infection could be ruled out; they had never been on business trips, had never used public toilets, or swam in swimming pools... So, where did their illnesses come from? After analysis, it was found that their hands might be the culprit of infectious diseases.
In daily life, many couples do not have the habit of washing their hands before going to bed. They may have read public newspapers or counted banknotes before going to bed, and their hands may be contaminated with sexually transmitted disease pathogens. During sex, they use their hands to touch their own or their partner's sexual organs. In this way, both spouses may become victims of STDs. Girls give themselves 5 minutes before sex.