A user just created the_pose tag and wiki. Examples of what he's using it for: post #1819266, post #664814, post #1403876
Wiki says:
Popular foot fetish phenomenon.
A view of the characters body that expresses their ass, legs and feet while lying flat on their stomach, typically viewed from the front with the face closest to the viewer.
Subject can be clothed or unclothed, but their feet must be bare as this is a term coined by foot fetish enthusiasts to express feet in a specific way.
I don't have an issue having a tag for a specific pose, but I feel using the name the_pose is rather ambiguous and that there could be plenty of other poses that someone could say is "the pose."