Boys who do not have a birth plan can choose condoms for contraception when having sex, but before using them, they should check whether they are within the shelf life, whether there are cracks, deterioration and so on. It is generally divided into the following four steps. 1. Tear open the outer package of the condom carefully and do not let sharp objects touch it. 2. Carefully squeeze out the residual air inside the condom and put it on the penis after erection, making sure that the end of the condom is exposed. 3. Ensure that the condom remains tightly attached to the penis during intercourse. If the condom slips partially off during intercourse, it needs to be reapplied. If the condom falls off accidentally, you need to replace it with a new one. 4. To avoid semen leakage, after ejaculation, while the penis is still erect, the man should squeeze the bottom of the condom tightly in his hand, withdraw it from the woman’s vagina, take off the condom, wrap it in paper and throw it in the trash.