From daddyphysio.wordpress.com/2... we see that firm pressure on the upper lip leads to visible deeper inspiration and is a form of breathing with a tight upper lip.
Tightening the upper lip is essential for healthy breathing. Just take a look at videos of Barack Obama with vigorous lip movements. In contrast you can hardly breathe through the mouth at all with slackened off lips. Seems like lip action is the priority. What do folks think?