Besides shit on your dick (this is why I usually wore a condom during the halcyon years of three or four tricks a night at the tubs in the 70's) I have an even worse Real Horror Stories from the Tubs, circa 1973.
I had a regular customer, a young nelly sweet guy, who would try to suck on the backs of my arms (figuratively) when I tended bar in the Castro. He was sweet and since it I was semi-famous for my "endowment" he never ceased to teasingly chase after me. But I never led him on. And he always tipped especially well. He was an RN from Oakland.
One day he just "disappeared" and I didn't see him for about two years.
Then I ran into him at the Rich Street Baths one evening. I was glad to see him and we sat at the lounge bar chatting about why he'd not been around. His story was a bit alarming. Two years earlier he had hit the tubs after the bars closed and found some daddy-type who fucked him senseless (his favorite thing) and who was also willing to stick around and fist fuck him.
If you've ever been to the baths/tubs/saunas, usually you are given a key to your room or locker that is attached to an elastic (and microbe infested) ring of bungie-cord-like material that you can wear around your ankle or wrist. I used it as a stretchy to keep my long hair in a pony tail. My friend's dream boat daddy had his room key on his wrist and neither my friend or his dream boat daddy realized that while the daddy fist-fucked him, the key was creating deep tears in the lining of his rectum. But my friend was in such a heightened state that it apparently did not occur to him that some of the pain was not normal.
After their fist fucking session my nurse friend quickly showered, dressed, found his car and headed for the Bay Bridge. Once he made it back to Oakland, in addition to some constant and increasing pain, he noticed the seat of his pants were wet --- with blood. He drove directly to the emergency room of the hospital where he worked for immediate medical care. In addition to pulling out the elastic band with the fist daddy's key still attached, they had to spend several hours stitching the gashes and deep wounds the key had created in his rectum.
True story. Never found out what happened to his fist daddy. But it was years (as in decades) before my friend, a committed and born bottom, ever engaged in anal sex again.
Personally, I would have gone to a different hospital emergency room, but that's just me.
Oh, and on a happy note, he is still alive, still working as an RN, HIV-, and just as much a flaming screamer as he ever was.
Just thought I'd share.