Barriers for oral sex

Use a new barrier for every sexual act and put it in place before any mouth-to-genital or mouth-to-anus contact. For mouth-to-penis, use an external condom: check the expiry date and the wrapper, open it carefully, put it on while the penis is erect and before any contact with the mouth, pinch the tip and unroll it to the base. Use a water- or silicone-based lubricant, avoid oil-based ones with latex, and when you finish hold it at the base and throw it away.

For mouth-to-vulva, use a dental dam (a latex or synthetic sheet) or, failing that, a condom cut open to make a flat sheet. Lay it over the vulva before you start; a water-based lubricant on the side against the skin improves the feel and helps it stay put. Do not flip it over halfway: if it moves, use a new one. A new one for each act, and never shared.

For mouth-to-anus, use a dental dam or a barrier sheet over the anus. This contact can pass on gut microbes as well as STIs, and the barrier helps lower that risk. If there is diarrhoea, pain, sores or irritation, it is better to leave it until you are well.