How can I visualize two arm movements?

In certain recordings I would like to sync, or visualize arm movements to make both arms move about the same speed and height to each other.

Say I want to record an "I want to give you a hug" scene and have both arms come up with the motion of an open arms for a hug..

I only have one mouse to move one arm at the time.

On the second recording I can't view the first recording of the first arm, so recording a second arm movement to make it match with the first arm movement is not that exact. 

Is there a way I can work around this?