Stand in front of a wall and place your hand or fist on the wall (or on a pole, whatever serves the purpose) and move to escape from your friend with a stick or anything with a good reach. Keep moving when you are hit and work to disarm the partner. Learning to work while being afraid will clean you from unwanted movement and give you better access to your true actions. Another way to get there is to walk with your eyes closed and have a partner or more place a heavy staff in your way and when you contact them you learn your first reaction without having to wear a social mask over it.
Stand naturally and lift one leg slowly without moving the hip to compensate for the mass shift. Do it slowly and a few times in different directions. Another way to do this is to use a gun or a simple lazer pointer like the kids use for presentations to mark an X on the wall and keep it there without shifting as you lift your legs. Later on do this as you walk and as you walk and shift from target to target. You can get a non Systema friend to help with moving targets as you can always ask friends to shove you around and hit you with staffs. It reveals a lot too about their nature.