Occurring in either the vaginal or anal region.
But, to answer your question: I have seen fisting discussed openly on Vegas P4P boards. It gets asked about on
TER Vegas on what seems to be a monthly basis. If you're looking for a lady who offers it, an ISO is sure to get you some PM's. I will say, not every lady who is open to it will want to comment publicly or make it known. To each his or her own. Why does it need to be discussed at all? If you wanna slide your hand wrist-deep in some lady's hoohah or back door, there are plenty that are into it