It’s less likely for a guy who is topping to acquire HIV, but transmission can still occur. How does this fit into decisions around sex?

Though topping carries a lower chance of HIV transmission than bottoming, it is still a common way that guys acquire HIV. This is because HIV can be transmitted through the tip of a top’s cock or through his foreskin because of rectal fluids, vaginal fluids, or small amounts of blood in the bottom’s ass or front hole. This is even more likely if the guy bottoming doesn’t know he is HIV-positive, and therefore has a higher viral load.

There is strong evidence that the foreskin is important in increasing the chance of getting HIV when you top. But when this has been looked at for guys who have sex with guys, the benefit of removing the foreskin is not as clear. This is because the vast majority of guys both top and bottom.

Choosing to top as an HIV prevention strategy will always be more effective if the guys involved are using other strategies like PrEP, have an undetectable viral load, or condoms.