Part of what makes being a kid fun are secrets. Secret passageways, secret handshakes, secret interests. Those are the things they have all to their own and that adults can't infringe upon.
He made this gesture all on his own, but combined with the subtle smile of his mouth and eyes, looking at this shot I can't help but wonder what is going on in that secret world of his.
This one is my application of the Strobist headshot in a corner tutorial. I was going for a very soft light look, so I put the flash/umbrella as close as possible to his face as I could without actually having it show up in the frame. This created relatively soft shadows (i.e. gentle transition from black to the underlying color) on the camera right side of his face, as can be seen next to and below his nose as well as in the shadow cast by his head on the wooden chair-back to camera right. By cranking the flash power way down, I was able to open up the aperture to get a shallow depth of field, blurring the plain-Jane background wall to soften it's look to go along with the lighting theme more.