I would say about 15 - 20 % of the women I've been with in my life rimmed me. Only a few freaked out when I did it to them and stopped me. Now there have been one or two that didn't seem to care when I did it to them, but didn't really love it. One in particular had the nicest, firm, round ass and I camped out down there between her buns as she laid on her stomach. I ate her and tongued her ass for at least an hour, and when then asked her if she liked that. She said, "It kind of tickles".
One who was really into anal really got off when I tongued fucked her ass.
However, women that give that I've been with have to be really comfortable and not care about the guy thinking she's some kind of asslicking slut. My first was a girl I dated off and on for years, and early on she gave head, but not very passionately. Near the end of our time together, she became obsessed into sucking cock, and would lick and eat my ass like crazy. Several others that I have been with, started licking and fingering my ass during our first time together, and were actually more pre-ocupied with my ass than they were with my cock. And a couple of others were very submissive and loved to be told what to do and loved to be ordered to lick my ass.
So it takes all kinds to lick an ass. Some like the dirtiness and slutiness of it, some are must into guys asses. And some hate it.