Backing up is the same as going forward. Put your dominant hand on top of the steering wheel. Move the top of the steering wheel in the direction you want the vehicle to go. Be conscious of the fact that the front of your vehicle will swing outside your line of travel as you back up. That means you need to leave an extra margin of safety space around obstacles.
Backing up is NOT the same as going forward when you are backing a trailer. It is the opposite. The way to "intuitively" back up a trailer is to place your dominant hand on the bottom of the steering wheel and move that hand the direction you want to go.
You will gobble up even more space backing up a trailer. So leave extra, extra margin around obstacles.
Backing up without trailer: Dominant hand on top.
Backing up with trailer: Dominant hand on bottom.