Our character is trying to show that he (usually a man, occasionally a woman) is cool, casual, and intent upon whatever is being said by their superiors. The character does this by artfully leaning in a doorframe, putting one foot up on a chair or other set-piece, or flipping an armless chair around and sitting facing the chair-back. While not always taking part in the dialogue, they are engaged in the scene as an on-camera observer, and ready to interject an idea or quip. Contrast the Captain Morgan Pose, where one foot is placed forward in brazen display of one's balls leadership prowess.