From an interview with Deborah Addington in Vice Magazine:
A few months ago we featured some photos from a young lady who takes pictures of all the weird things she finds while working at a thrift store. One of the gems she discovered was a book by Deborah Addington, called A Hand In the Bush - The Fine Art of Vaginal Fisting. Needless to say, I was intrigued, so I ordered the book from Amazon the next day. Part of me thought the book was a joke. I imagined it to be some sort of satirical, voyeuristic look at a black belt-level sex move most people don't have the gusto to try for themselves. I couldn't have been more wrong.
A Hand In the Bush is an excruciatingly didactic field manual for anyone who has ever considered getting wrist-deep in a vagina. After reading this book, an arthritic virgin could navigate their hand into a woman with the confidence of a seasoned pilot easing a 747 into its hangar. The book includes graphic illustrations of everything from regular old vaginal fisting to mutual fisting to the mind-boggling double fist (pretend you're applauding, only don't pull your hands apart).
VICE: Your book is called The Fine Art of Vaginal Fisting. Do you really consider fisting vaginas an art form? Deborah Addington: I do. We all have fingers at the end of our hands, but a lot of people don't organically look at their hands and go, "Gee, I could put that in a bodily orifice!" So you're taking something that preexists, reconfiguring it, applying creativity, and producing a spectacular result.
How many and what type of doctors did you consult during your research for this book? I talked to three doctors. I also spoke with a registered nurse practitioner who dealt with a lot of sexuality issues. All but one of them were OBGYNs, and the one who wasn't is a kink-friendly physician out of the BDSM community who specializes in dealing with what a lot of other people might be balked by.
Had any of the doctors tried vaginal fisting? I know two of them did for sure. The other one was a clinician who was dealing with getting all of the anatomical information, and they might not have been into fisting. I'm not sure.
Read the rest of the interview, and lots about fisting, here.