I was just wondering how many women lick a dog's ass during sex. I have seen it in some dog porn movies, especially the Japanese MAD Gloryquest series, but I was just wondering how common it is in private
You mean the AAA porn - Asian animal abuse.
I can not imagine how you would do a rimjob to a dog while having sex with it. The physical arrangement at that moment of sex is not really allowing that.
There are some rimming threads. Generally it is not very common.