^x2: Obviously he's demonstrating how a new feature in LuniaZ allows the player to control their character by smashing their head into some pre-cut ceramic tiles. The more tiles you smash, the better the combo the character performs. This particular action is equivalent to AAAAA as Sieg.
A less likely scenario is allm attempting to say goodbye to the Lunia name in a symbolic manner as it is being replaced with LuniaZ, seeing how the tiles had the former logo on it. It also would help the press conference stand out a bit I suppose... But I could be completely wrong about this, best stock up on ceramic tiles ahead of time, imo.