What's with the fist on the chin pose?!

[Pretty.in.Pink]

Hi fellow Phi Mus! I'm a recent alumna (graduated last year) and I'm still very involved with Phi Mu, so I was surprised to see a new Phi Mu "sign" this Bid Day that I had never seen before! I noticed at several Southern schools (particularly in MS) Phi Mus were posing with their fist under their chin (kind of like "the thinker").

I have NEVER seen this before and I'm kind of confused as to how it relates to Phi Mu. At first I thought it was just silly posing, but I saw multiple Phi Mus do it at different schools, and they called it a "sign" for Phi Mu.

Help? Some Googling led me to believe it might be called the "Phi Mu swerve"...