The exact proper puckering of lips and sucking in of cheeks most often used in self-portrait photos taken for Facebook or other social media.
A mobile device is most-often used by the subject of the photo and held at a downward angle. This eliminates any chin and also shows cleavage - both are indicative of girlfriend lips.
The exact purposes for this pose remain unknown, however, among the various motivations: to appear slutty, to attract the lowest common denominator of male, to make oneself appear more thin than is actually the case.
Say there, my brother, indeed, it is difficult to discern the attractiveness level of these bitches seeing as how they all pose with the girlfriend lips.
All of the chicks on my Facebook do the girlfriend lips in their picture. Why don't I ever see them do that in real life.