I know, right? Well, the pic will explain:

When I started teaching, I found myself using my arms - and not for writing on the whiteboard. I started teaching Geometry, but found myself teaching solving equations with the embedded Algebra. I would make my arms look like a teeter totter (see saw) and talk about taking away from one side, what happens when if you don't take away from the other side? We reminisce about playing on one, and inevitably someone departing the teeter totter and us falling on our butts.

It wasn't until I started teaching Algebra 2 that I found myself using my arms to show end behavior. Positive even functions are "Dance" (2 arms up, fingers pointed), negative even functions are "Bernie" (like from Weekend at Bernies-it's a dance my students have taught me recently) and odd functions (positive and negative) are "Disco" (like John Travolta)