Nice tones. I think your choice of lighting is interesting but a bit strong over on the right side of the photo. Have you experimented with changing the direction and the intensity? I'm thinking perhaps reducing the intensity and adding a 2nd light or reflector from the left-rear to add a bit of counter illumination.
As for the pose, hey, whatever does it for you, big guy. :P
If he's in the "mood" for what I think you're inferring, he doesn't look that excited. He actually looks kind of bored. I do like the lighting though, but not for this expression.