During battle you might notice the 4 small boxes beneath Travis’ avatar. This part of the interface refers to your currently selected Sushi. Using the Left and Right D-pad (Directional Pad) buttons you can select Sushi from your inventory. The color of the Sushi matches the color of the 4 squares. This gives you a quick indication of the Sushi you are holding. Press Up on the D-Pad to use.