There are some STI risks associated with performing oral sex on a penis, so I am happy to provide some more information on that.
Many people don’t realize that STIs (sexually transmitted infections) like chlamydia, gonorrhea, HPV, herpes and syphilis can be acquired by performing oral sex on a penis if it has one of these infections. Hepatitis B and HIV are not commonly passed this way, but may be possible under certain rare circumstances.
If you give a blowjob (or put your mouth on a penis) without using a condom you may want to be tested for these STIs. During a testing appointment, a sexual health assessment is usually done. This is an opportunity to let the clinician know what kind(s) of sex you are having (oral, vaginal, anal, manual, shared sex toys…) so that they can help you decide which tests are best for you. Often STI testing involves blood work or a urine sample, but sometimes it may require a swab of the throat as well. Being open about your sexual activity can help the clinician get a better idea of what to test for.
Keep in mind, STIs often don’t have visible symptoms. So we recommend using a condom even on a penis that doesn’t “look like it has an STI.” I would also recommend talking to your partner(s) about making STI testing routine, so that if they have an STI they can take steps to clear it up or manage it to avoid passing it along.
I hope that helps clarify a few things for you.