Repeatedly “tipping the nose”, “scratching the beard”, “furling hairs” and covering the throat with the hand are treacherous gestures.
Also sudden changes in body posture, such as a powerful “self-hugging” or the interlacing of the legs can be a sign of weakness.
And the negotiating counterpart will intuitively grasp this and use it unconsciously (or even consciously) against you. For example, making an impudent claim right now, or applying an unfair attack.
And your hand gestures and your physical activity will also help to reinforce the process that has made you weak.
See here a very interesting TED-Talk by Amy CUDDY>>>
In order to protect and to strengthen yourself, you should pay attention to your gestures and posture. The easiest way to protect yourself is to sit upright!