Surprised this did not come up earlier in the chain.
If a lady is willing to take a man's cum in her mouth, that is her choice.
Both in the hobby and out, I have never asked, suggested, or demanded it. Confirmation with a provide while she is blowing you is a polite thing to do before you blast away. Seems rarer now, has not happened to me in almost a year. COVID I suppose.
Once, and only once did I get a taste of my own. It was in the 80's and I was a bit loaded. After I had shot my load my GF at the time thought it would be funny to slip a some on her tongue then kiss me. NOT funny at all. OMG did it taste AWFUL! Never,ever, ever have I tasted myself since.
How in the world can a women tolerate the taste? Pineapple juice can help, as I have been told, but YUK.
A while ago I was lucky to visit Trixxie Love. She makes no secret about performing CIM.
I asked her how she could stand the taste of cum. Her answer was simple, "like beer it is an acquired taste".