Masturbation (sometimes called ‘mutual masturbation’ if you’re masturbating with a sexual partner) is generally regarded as one of the safest sexual activities.
Because you’re not putting any bodily fluids inside someone else, then the risk is pretty low for most STIs. However, once someone has climaxed and there is cum present, that cum can be a way for STIs to get transmitted, if he has any. If you’re worried about infection, simply wiping up the cum is an effective way to mitigate the risk.
In 2021, there was an outbreak of monkeypox – a virus that’s passed from person to person by contact, like rubbing against a person. Masturbation and frottage (rubbing yourself against another person sexually) is considered a good way for monkeypox to be transmitted. There’s a safe, effective, and long-lasting vaccine for monkeypox, and we recommend you talk to your local clinic about getting it.