Bottoms should be smart enough to know they should be clean for butt fucking....duh
I lost a fuckbuddy recently because of this. I've played off and on with this guy for about 20 years. He is my age, good looking, nice body, 6" average thickness. He was the next-door type of guy. He always dresses nice and was always clean. We used to see each other at the bookstores and we had a thing where if it was really dead (which happened many times) or there wasn't anybody worthwhile there we would mess around. We usually would wait a while before we started, we would give it an hour or two. We never discussed it or made plans, but I bet we have hooked up like this about 100 times. Even though we rarely talked to each other, I knew him pretty well, sexually at least. But all we ever did was suck each other and some ball play. He really enjoyed his balls being played with roughly. But in those 100 times, we never did anything anal.
When I started hosting at my gloryhole, I stopped going to the bookstores and I didn't see him for a while. One day, I got a message from a headless guy on Grindr. He said he loves gloryholes and wanted to play. I invited him over and when he got there, I recognized the body and the dick immediately, it was my bookstore buddy. As far as I know, he didn't know it was me, but we got busy doing the usual, suck each other off and roughly grab each other's balls. At one point, while sucking me off, he pushes on one side of me to get me to turn around. So I do it and he starts rimming my ass. Okay, this was new. He rimmed me for about 5 minutes, turned me around again and sucked my dick for a few minutes. He then stood up and put his dick up to the gloryhole. So I started sucking his dick. He then turned around and put his ass up to the hole. I normally didn't rim guys and I have never mentioned it to him. I can only do it if I know it is super clean. So I stuck my finger up to his hole and NOPE! NOT CLEAN! NOT EVEN CLOSE TO BEING CLEAN! I grabbed a towel and wiped my finger off but that smell was stuck in my nose. I wasn't sure what to do, so I turned him around again and just sucked him off. I got him off and sent him on his way.
He kept messaging me for a few months. I just kept telling him I couldn't host, but he never got the hint. I didn't want to block him because we played together so many times, but I couldn't get his dirty ass out of my mind. So finally I told him why I wouldn't invite him over. He said he didn't realize, he would never do that, but I don't know how he couldn't have known. I did eventually block him. I just cannot get over it.