HIV through underwear help??

Hi just have a question about my risk in a situation with a guy a month or so ago.

I was a bit drunk during this so my memory of its a bit hazy, basically i was rubbing his anus through his underwear and it felt a little moist, then he positioned my penis (unprotected) near his anus and sat on it, he was still wearing underwear at this point. My penis is bent forward so it doesn't go in very easily normally but i did feel a lot of pressure on my shaft, this lasted a few seconds and i can't recall if there was any penetration, but say if there was he wasn't riding my penis he was just sitting on it, is there a chance anal fluid could have seeped through the underwear and somehow gotten into my Urethra, please help I'm wrecked with anxiety over this!

[joggen]

No risk.