I dunno how to post pictures either or I would.
It is likely that he is closing a keyhole. when you watch it in the tgs 2004 trailer, there appears to be a door there although obscured by his aura, when the camera pans behind him. *edit* also in jump fiesta 2005 trailer, the door is more visable there.
However it it may not be the standard key hole closing ritual as depicted in the same trailer, where he closes a hole (a small one, like 15 feet up) just after Auron tangles with Hades and Cerberus, where Sora has no aura and is holding the keyblade with only one hand, with more of a get it done and go home attitude from KH 1.
So I would assume that if he is closing a keyhole in the scene being discussed, that there is something special about that one in particular.