My favorite yoga book is Ashtanga Yoga: The Practice Manual by David Swenson. This is not some kind of amazing tip, most people who have a few yoga books will tell you the same thing.
I like this book because he says stuff like, “it is not necessary to be a ‘tight ass’ in order to engage Mulabandha.” Plus the instructions are very thoughtful, with details on things like where to direct your gaze, how to hold your feet, and so on, that lots of books leave out. And there are lots of variations for when you look at the picture and start laughing and laughing. There is a nice mix of between poses that are alternately “practical”, “inspiring” and also “hilarious.”
Case in point: Pindasana, The Embryo Pose, pictured above. First I thought, nooo…, and then I thought, maybe? I love Ear Pressure posture, which is the same except you are not in that horrible leg knot, err, lotus, and your arms are on the floor to balance you.
One reason to try this pose is if you enjoy exploding out of a posture, rolling across the floor like a weeble people, and landing with a whump on your rump. While undignified, it is hilarious to others, especially if you do not become dead or permanently injured in the process.
In sum, if you are looking to break your neck, I cannot recommend the position above highly enough. Enjoy!