How vigorous the sex is
The inner surface of the anus and vagina and the surface of the penis are very sensitive and delicate.
The rougher or more vigorous the sex the more likely that microscopic abrasions and friction can damage the surface.
This damage is unlikely to be visible.
Any cuts or tears can act as entry points for HIV in infected genital fluids.
Lubrication can reduce the risk of this damage.
Slippery sex is much less likely to damage genital tissue.
Last updated: 1 December 2019.