I learned this stretch from a physical therapist friend. It targets the forearm muscles that get overworked from operating controls. I do it for 30 seconds on each arm before and after my shift. My elbow pain has almost gone away since I began.
Totally agree, it's a weird one at first. @the_max is right about holding it longer, that made all the difference for my lower back. I do it for a full minute now and feel way looser.