I doubt any women enjoy rimming a guy, any guy, let alone some repulsive john. The sex workers obviously do it for the money. If her half fag john likes it, he'll go back to the woman who provides it. But I'm a normal relationship, she might do it to please her man, maybe that keeps him from wearing her panty hose and dresses ;-)
Out of all the women I've been with, I only rimmed two, but they were young and SMOKIN HOT, had DELICIOUS pussy and we'd 69 a lot. So when super turned on, and eating her for 30 to 45 minutes, a good part of that time with her anus one centimeter from my tongue, of course I'll lick that, but it's never my go-to area and they didn't care for it much either.
So if you are with a woman you like it at least don't want humiliate, don't ask for that. Just think that when you kiss her, do you want her to have just finished tonguing some disgusting pos loser's anus?
Just because she's a sex worker and you're paying her, doesn't mean you should treat her any way other than you'd treat your wife or gf (which hopefully you don't have while seeing a sex worker).