We all know to check our back seats after removing a prisoner. To ensure control of your subject while doing so unassisted, try this tip.
After removing the subject from the back seat, have your subject lean forward against the rear wheel well/door area of your car with their feet apart.
Assuming you’re removing them from the passenger side rear seat, place your left knee/shin into the “soft spot” or calf area behind their right knee.
Apply pressure necessary to maintain sufficient contact and control thus “pinning” them to your vehicle.
Adjustments may be necessary based on your physical size and that of your prisoner.
You can now quickly and safely check the back seat area. If removing them from another side, reverse the process by using your leg closest to them and continue.
I have used this method for sometime on subjects of all shapes and sizes with great success.