I have been seeing a guy (university student) since the 2nd Sept. We did once protected anal sex and frottage. He was tested in front of me negative on the last weekend with 3rd gen rapid test. I'm hiv- too. But today, we did the protected anal sex again. Before we performed this, we were frottaging (his underwear was off, mine still on), this was the time when the trouble begins:
He pressed his penis so hard all in a sudden to my anus without lube and tried to do this with sliding the part of the cloth on my anus away. I was very alarmed about this, since I never have the intention of getting infected. I can tell that was not pain and not that typical penetration, but just being invasively pressed on my anus. After that, I tried to check if my underwear on my anus was still there and it was partly covering my anus.
My question is:
1) Am I in risk of contracting the HIV virus?
2) What's the difference of frottage (if it was) with or without underwear?
I'm really worried about this and need advice on if I need to get prep. Many thanks!!!!