[everforward]

It depends on the sexual activities undertaken.

HIV/AIDS is extremely rarely (maybe never) sexually transmitted in female-female intercourse. The CDC notes a "negligible" risk of transmission from sex toys.

HIV/AIDS is contagious through vaginal intercourse. Transmission is fairly low, though certainly not risk free, because most people aren't bursting blood vessels during typical vaginal intercourse. It does happen, though.

HIV/AIDS is most contagious through anal intercourse, and especially for the receptive partner. This is, as far as I know, regardless of the sexual orientation of the participants (presuming there's an actual penis involved and not a toy).

The CDC has data at https://www.cdc.gov/hiv/risk/estimates/riskbehaviors.html

Long story short, it's probably not worth it for most people unless they're engaging in unprotected anal sex with people who have unknown HIV status.