Several behaviors put people at highest risk for STDs, including having unprotected sex (especially with several partners), having unprotected sex with a prostitute, and sharing needles during injection drug use or body piercing and tattooing. A woman whose partner is bisexual may be at higher risk for becoming infected with a sexually transmitted infection if her male partner has had unprotected sex with male partners either while they are together or in the past. In addition to avoiding these behaviors yourself, you must choose your partners wisely, because not only are partners who engage in high-risk activity at risk for acquiring an infection themselves, they may infect any sexual partner they are with. A partner who has sex with other partners while you are together puts you at risk for sexually transmitted infections.
People who exchange sex for money or drugs, such as prostitutes, are at very high risk for transmitting STDs. Those who have sex with prostitutes have a high risk of acquiring infections. Any type of sexual contact—oral, anal, or genital—with a prostitute is high risk. If protection is used, then this risk is decreased, but condoms may break or leak, so there is still risk. Some people are under the erroneous assumption that receiving oral sex without a condom from a prostitute is safe. But if a person performs unprotected oral sex on many people, his or her throat can become a harbor for infection just like the genital or anal area.