the woman puts a condom in her mouth and uses it as a barrier between her tongue and your ass so her tongue never actually has contact with your asshole.

I'm kind of in favor of the practice, licking an uncovered anus seems rather unsanitary to me no matter how much washing you do, and I certainly don't want to kiss a woman that tastes like ass. lol

I once asked a lady in the middle of some exciting foreplay if she minded if I inserted a digit or two inside her. She said she did mind, but was enjoying me and asked how bad I wanted to do it. I enjoy fingering a girl so she grabbed a condom, put it on my finger and told me have all the fun I wanted. It was a little odd, but she felt safer and more comfortable and I still got to have fun. Sometimes you have to compromise.

Some things I imagine just aren't fun with a condom though. For me, it seems that a condom would totally kill the sensation of rimming. Who knows.

What's the point?

Not that I'm promoting the practice, and I haven't done it in about a year, and then only with my LTR partner(s) and a couple of AFT guys, but like somebody else said, what's the point of covering it.  It would be about like licking a plastic bag or like having somebody rub one on you.  Not the same sensation at all.  

However the downside is passing diseases, and while it's pretty fun kink, it is kinda nasty.  But then I'm a kinda nasty girl, sometimes.  LOL

Best,
TS Jamie