Bonk
As this book is about sex and everything it contains (dysfunctions, mysteries, experiments, medieval practices and animal ..uhm… observations) it’s a bit of a challenge to write a PG rated review. In true Mary Roach style the book is full of facts, the stranger the better, and she even participated in some of the experiments to the chagrin of her husband.
If you are a fan of her books then this one should not be missed. If you have never read any of her treasures and is not overly squeamish I would rather recommend starting with Stiff: The Curious Lives of Human Cadavers
Now I am off to go find a mirror and a measuring tape ☺