The phrase "right bumper" refers to a button on a video game controller. It is typically located on the right side of the controller and is used to perform specific actions within the game. Full definition
Holding the top right bumper button will let you move both characters simultaneously. (en.softonic.com)
If this controller keeps the original feel to it then we have to ask: Will it trade out today's left and right bumpers for the black and white buttons? (cultureofgaming.com)
You will eventually gain powers that you can switch to on the fly using right bumper. (jgghgames.com)