While lying supine on the floor or table, I ask the student to inhale as deeply as possible, then exhale completely. As they are exhaling, I ask them to note how their lower back presses into the floor and the tailbone curls up slightly. I also use this opportunity to explain this is an “imprint” so they will recognize the cue when mentioned. Then I have them continue holding this position and “feel” themselves breathing into the rib cage. To do this, I ask them to place one hand on their lower abdominal muscles and one hand on the side of the chest. As they breathe in and out, the ribs will expand and contract while the lower abs should remain as still as possible.
In addition, I often explain how this technique works using a brief description of the diaphragm and how it relates to breathing. Rarely have I had to explain breathing much beyond this demonstration – it works great!