
Rimming is a risk for some infections, especially hepatitis A (which you can be vaccinated against for free at clinics). There have been no recorded cases of anyone getting HIV from rimming someone, and one case of someone getting HIV from being rimmed.
The only possible risk would come from cuts, sores (including herpes), bleeding (eg, from haemorrhoids or warts) around the arse of the guy being rimmed or on the mouth of the man rimming. Broken skin, tiny cuts and bleeding is more likely after anal sex, fisting or arse play with dildos. You might want to avoid rimming after doing these. Blood can occasionally be in shit too.
If you're worried about any infections you could rim through a barrier, like a condom cut into a square or non-microwavable cling film.
Vaccination against hepatitis A is a must if you like rimming.
Infectious levels of HIV have never been found in piss and there have been no reported cases of the virus being passed on during water sports (including taking piss in the mouth). Urine on unbroken skin is safe. If it gets in the mouth, in the arse or on skin with cuts, rashes, etc there's a theoretical risk but only if there's blood in the urine. Blood can be in piss if someone has kidney stones or a bladder infection.
There have been no recorded cases of HIV being passed on in piss.
If a condom breaks and you’re worried about HIV being passed on or picked up, PEP, a treatment that can stop someone getting HIV if taken soon enough, might be available. Click here to find out more.