How do I add a relative force to the bottom of a cube?

Hi, I’m moving a cube and need to add a relative force, but it needs to be applied to the bottom of the cube otherwise it’ll be pushed over.
I know you can use AddForceAtPosition() - but I want to use AddRelativeForce() - relative to the cube’s coordinate system.

Take a look at this screenshot. Lock the axis you don’t want the force to be applied to. I believe it should be the Z axis.

I hope this helps.