I'm in my mid 30s and honestly dont know. Is it contracted by semen? Or any sexual physical contact.If you dont use a condom at first, and then before he ejaculates he puts one on. Does this decrease the chance.
A person with an STI can pass it to others through contact with skin, genitals, mouth, rectum, or body fluids. This includes contact through vaginal sex, anal sex, or oral sex. Even if there are no symptoms, your health can be affected
Some STIs can have no symptoms. The best thing you can do is to get tested regularly, encourage any partners to as well and use condoms consistently and correctly if not in a monogamous relationship. STIs can be contracted from pre cum ie before full ejaculation or for some from skin on skin contact.