Unless you abstain from sex entirely, you are always at some risk of contracting a sexually transmitted infection (STI). Regular testing for STIs is important for all sexually active people. STIs don’t always have symptoms and you can pass on an infection to a partner without realizing it. Their incidence is rising dramatically, especially among men who have sex with men (MSM) and transgender women.

The PrEP protocol recommends STI testing as often as every three months. Bacterial STIs such as gonorrhea, chlamydia, and syphilis are easily treated—and the sooner the better, both for your own health and to help reduce the spread in the community. If you test positive for an STI it is important to notify your sex partners. (If you prefer to remain anonymous, you have the option of letting a public health department or another free service do the notification.)

Treatment can be inconvenient, and in some places expensive. Many people prefer to avoid catching STIs in the first place. There are a few risk-reduction strategies people try -- with varying degrees of scientific evidence.

1. Condoms. While many of us don’t particularly like them, condoms provide very good protection against many STIs. They aren’t perfect (and it’s important to be tested regularly even if you use condoms). Most STIs (other than HIV) can be contracted orally or even through skin contact, and few people use condoms for oral sex. But the risk is cumulative: using condoms for anal/vaginal/front hole sex significantly reduces your overall risk, even if you don’t use them for oral sex. The research is mixed, but one summary found that condoms reduce gonorrhea risk by 80 to 85% (similar to their effectiveness against HIV), syphilis by 50 to 66% (highly variable because the sores that transmit syphilis are not always covered by a condom), and chlamydia by 26 to 85%.
2. Partner selection. If you limit your circle of sex partners to people who test frequently for STIs, you might still contract one, but hopefully, you will find out sooner (assuming everyone is responsible about partner notification) so you can be treated promptly. It is also basic math that people who have less frequent sex or fewer partners run a lower risk of STIs -- just as people who drive fewer miles are at less risk of accidents.
3. Mouthwash. Really. A major vector for gonorrhea (including the only cases to date that were resistant to first-line antibiotic treatment) is oral sex. Gargling with an alcohol-based antiseptic mouthwash like Listerine has been shown to reduce the risk of pharyngeal (throat) gonorrhea. In a trial of 196 MSM, those who gargled for a full minute daily with Listerine had a significantly reduced amount of the bacteria in their throats -- and an estimated 80% reduced risk of testing positive for gonorrhea.
4. Peeing after fucking. This one counts as “folk wisdom.” Some people claim that urinating after sex can cleanse bacteria from the urethra. There is no research to support this claim; however, some studies have found fewer urinary tract infections in women who urinate after intercourse.
5. Washing your junk. File this one under “it can’t hurt.” There’s no evidence that washing yourself after sex reduces your risk of contracting an STI. But frequent washing (of hands too) is basic good hygiene. It’s certainly considerate of your partners—especially in group sex situations. A penis that is going from one hole to another is less likely to transfer anything unwanted if washed between partners. Some people use an antiseptic skin cleanser like Hibiclens. (Note: hand/arm washing is very important for fisting, too. Because of the high risk of transmitting pathogens including Hepatitis C, fisters are strongly encouraged to use gloves -- a new pair for every partner).
6. Lube, not spit. Saliva can transmit the bacteria that cause gonorrhea. A small study found that using spit as lube for anal sex increased the risk of rectal gonorrhea by 40%. If you can, use commercial lube instead. (Same goes for fingering).
7. Antibiotics. Regular use of antibiotics, even without a positive test, to reduce the risk of certain STIs. There is some evidence of the effectiveness of this practice, but for several reasons, it is not recommended by experts. For more information, read this article.
8. Anal douching after sex. NOPE. Definitely not recommended. Douching is not at all effective against STIs. In fact, too frequent use of enemas can irritate the lining of the rectum and increase the chance of infections.