Before you go putting your mouth “everywhere”, please read.
According to American Sexual Health Association, you can get an STI through oral sex.
During oral sex, you can give your partner your STI and you can get theirs. Not all STIs are transmitted through oral sex, but some are.
For example, if your partner has a cold sore (oral herpes) and performs oral sex on you, you could become infected with herpes in your genital area.