When we speak, we naturally utilize various parts of our body — such as the eyebrows, head, hands, arms, torso, legs, and feet — to emphasize a point… - Joe Navarro

One of the most important observations you can make in relation to the hands is noticing when they go dormant. When the hands stop illustrating and emphasizing, it is usually a clue to a change in brain activity (perhaps because of a lack of commitment) and is cause for heightened awareness and assessment.

If you wish to enhance your effectiveness as a persuasive speaker — at home, at work, even with friends — attempt to become more expressive in your use of hand movements. [...] Whether you naturally speak with your hands or not, recognize that we communicate our ideas more effectively when we employ our hands.

When we press our lips together, it is as if the limbic brain is telling us to shut down and not allow anything into our bodies, because at this moment we are consumed with serious issues. Lip compression is very indicative of true negative sentiment that manifests quite vividly in real time.