I am a breastfeeding mother - I had a friend not ask and start sucking on my nipple for about 5-10 seconds. I don't know their HIV status - am i at risk of HIV from this encounter because my nipples are "open" as a breastfeeding mother?
No risk, because HIV is inactivated in air and also in saliva so if they had HIV it is effectively dead by the time it gets into you. It doesn't matter if they or you have open wounds either. Only sex risk is unprotected penetrating vaginal or anal.