Well before the reverse prayer became part of the S&M scene, ancient yogis had noticed its benefits to the body. In yoga, there is no connection between the reverse prayer hand position and sex, and as I am demonstrating the pose here, I hope the S&M community will respect this blog entry.
Reverse prayer releases tension in the upper back, especially if you have been working at a computer, driving a car or sitting on a plane for hours. Hold the pose for a few seconds and breathe deeply into your ribcage. It is not the most comfortable of poses, but you can scream a little if you have to. If the hands can't form a prayer, hold on to your elbows behind the back instead. You will feel much better after a few seconds in the pose.