Man! When I was in the 101st we did that all the time! I thought it was just something looney the guys there cooked up as I never ran into it anywhere else.
Tried it at my next unit and the folks would stare at this circle I made with my fingers like *I* was looney.
I figured it was an FSU frat thing - none of the 101st guys were particularly into it unless the LT was playing, and I didn't see it anywere else in my career either.