Once you master this technique, proceed to mentally feel the external muscles of your body in a symmetrical way. That is, always feel both sides of your body, for example, both eyes, both shoulders, both hands, etc. at the same time. Begin by feeling your head, your scalp, your facial muscles and your jaw. Feel both eyes at the same time. Then attend to both sides of your nose, the corners of your lips and your cheeks. Next, mentally move down both sides of your neck at the same time and focus your attention on both your shoulders. Now, gradually move down your arms, forearms, and hands until each of these areas is completely loosened up and relaxed.
Now, return to your head and repeat the relaxation of your face. But this time when you finish your face, instead of going down your arms, go down the front of your body. Move symmetrically down the front of your body as though you were following two imaginary lines. Move down the front of your neck, your chest, your stomach. Continue until you reach your lower stomach and the bottom of your trunk. Feel the whole front of your body completely relaxed.
Next, return to your head, and go down the back of your body. Start with your scalp, with the top of your head and follow two symmetrical lines down the back of your head and neck through your shoulder blades and out onto your back. Continue to follow the two lines down each side of your back until you reach your lower back and the bottom of your trunk. Continue to move down both legs until you reach the tips of your toes, leaving the whole body very well relaxed.