There is a difference between sex and really GOOD sex, and that the difference demands deep understanding of what the other person is feeling, physically and emotionally. Interesting sex is about communication, using rhythm, time, sensation, and mood as language. It is amazing and frustrating how often otherwise appealing people don't get this. The woman who wrote this book gets it. She does an excellent job of describing why one fists or gets fisted in the first place. As aggressive as fisting sounds she makes it very clear that it can be, in truth, an incredibly intimate experience, requiring tenderness, empathy, and patience. If you already are into it, if you're thinking about getting into it, or your partner wants you to think about getting into it...then buy this book.