Lay on your back such that you are perpendicular (at 90 degrees angle to what your body-position would be if you slept in your bed) to the edge. Slowly start moving your body toward the edge, such that your head sticks out of the edge, then your neck sticks out. Now you can relax in that position such that your head and neck are arched toward the ground. You can continue this until either your shoulders stick out or your head risks touching the ground. Relax at every small bit of this out-of-the-edge arching. You may hear adjustment clicks.