The gesture involves leaning your entire body to the side and craning your head while twirling your wrist around the side of your head before finally cupping it up to your ear at the end of your lean as if to aid in hearing. It’s used when someone is hamming it up in front of a throng of people and they want more cheering. It tends to be a crowd pleaser.
An example of it can be found here (note: you will have to sit through an ad before the vid) during the Boston Red Sox victory parade. It occurs at approximately 28 seconds.
It’s not new by any means but I am curious about it. Does it have a name? Does it have a clear origin? Did anyone in particular popularize it?