Somatization is the process by which the kinesthetic (movement) and tactile (touch) sensory systems inform the body that it (the body) exists. In this process there is a witness, an inner awareness of the process.
In this somatization, Bonnie guides you through a pericardial and brain slow wave. "When I first began to feel this slow brain wave, as I said in my previous letter, I felt it initiate in my pericardium a moment before my brain. Rather like a pause before we take a breath."
You can find more about her experience with this slow wave here: https://www.bodymindcentering.com/pericardial-and-brain-slow-wave/.
Bonnies books and videos are available at https://bonniebainbridgecohen.com.