Character Costume Accessories
After selecting a character at the character select screen, you must decide which costume to use. When you confirm the costume selection you can also customize the costume in various ways by holding a specific button when you confirm your costume selection. Not all costumes are customizable, but when you confirm the selection, it makes a unique sound if a customization has been selected.

Button Input Customization
Shoulder or Trigger Button: Hairstyle/Head and Upper Body Items
Left or Right (D-pad): Glasses/Eyewear
X: Default Underwear/Undergarments
Triangle: Alternative Underwear/Undergarments 1
Square: Alternative Underwear/Undergarments 2
Triangle+X: Alternative Underwear/Undergarments 3