Withdrawal is a very old method of contraception, but many people still adopt it. It is estimated that 35 million couples in the world use this method, or about 8.7% of all contraceptive methods. The proportion used in developed countries is significantly higher than in developing countries. The advantage of the withdrawal method is that there is no need for contraceptives, nor does it require the guidance of a professional doctor, and couples can achieve satisfactory results after a period of cooperation. One of its disadvantages is that when ejaculating, you are determined to withdraw from the penis, which is easy to interrupt sexual intercourse and affect the couple's sexual satisfaction. Second, men often have a requirement to continue to go deep when ejaculating. At this point, the slightest hesitation may lead to the failure of contraception by inputting a small amount of semen into the vagina. However, in order to reduce the failure rate, those who use this method must pay a...