I only discovered how to move my ears when I was like 8 years old. This suggests the nerves are there, just very non-obvious to control.
I'd say a bit like raising my eyebrows, but the "tension" is behind the ears.
For me the tension is pretty far back, basically halfway to the back of my head on either side, and covers a vaguely oblong patch that is about 1.5 square inches.
Honestly it's not some major movement and I only have 1 degree of motion properly under control - I'm sure there's more that I can't. It's not a very significant thing irl.