I was 19 or 20, home from school for the summer. I was just learning fucking and sucking. Didn't know much else. Lol
I met this "older" guy, late 30s. He was a history professor at the local university. Well, he invited me over and patiently taught me to suck cock. Meanwhile, he kept plying me with beer. Eventually, I had to piss. (I miss that big old bladder. Lol) He stopped me and said don't waste it. Then, completely naked, we went on to his fire escape and I pissed all over him. Must have been a six pack worth easily.
I remember being shocked but not that shocked though I had never heard of water sports, had never seen porn with WS, didn't know it was a thing. Eventually, it became one of those things I've done occasionally but never got into completely, (though I do love a good piss up my ass), but I do understand its appeal for others.