From A Weak to Confident Communicator - 30 Day Challenge
Some postures help you gain confidence and put you into a positive body language. One such posture is what Leil Lowndes calls "hanging by the teeth."
Assume there is an invisible rope hanging from the ceiling. On the lower end of the ceiling, assume a key tied like shown in the picture. The key is hanging just above your mouth level.
When you have to make a speech or make a presentation, get into the posture where you bite the key with your mouth and hang by it. This posture stretches the right face muscles and places you into the body language of confidence.
Today, you must practice the hang by the teeth posture. Even if you do not have to make a speech today, practice the posture and find out how the posture feels like.