Lie on the ground and relax by rolling side to side a few times. Now have a partner come at you and press a foot to your body anywhere he likes (you can add to this by closing your eyes) As you feel the contact tense up your entire body and stop your breathing sharply. Do this a few times a keep the feeling in your memory for reference. Now as he presses his foot or knee if he wishes tense up your entire body to 100% and start breathing using puff breathing to vent extra tension out. After a few times lower the tension to about half of your maximum and relax your breathing so you only breath as fast as you feel you need to. Next tense up only the part of you which is pressed to the full ability you can (let go and move if you feel too much pressure) and later on use half of the tension.
Now that you are aware and able to manifest yourself the inborn fear response on several levels start to relax the part being pressed and add to the movement of the press by moving a part of you which is free so that the press will reach it’s direction but without you.
This is a blueprint for work and it can be done face up and down. Sitting, squatting and standing and later on in movement. I suggest you Add after a while several direction of pressing and see how your body finds a way naturally. Remember to free your eyes, keep moving and breathing.