The fifth posture is linked to the Mystic. Taking a modified Training Stance, sink down until the thighs are parallel to the ground. The knees are out at roughly 45 degree angles from the centerline, and the feet stay under them. The hands are held in the Sphere position, as taught in Jedi Breathwork.
This stance is very difficult to maintain, and because of that, it requires the greatest devotion and focus to maintain correct position. When down, feel the Force circle around the body: up from behind, over the head, down in front of the face, continuing the spiraling motion into the Sphere, building a dense energy ball. Breathing should be slow and steady, but not so deep as to rise and sink with the breath.
Hold this position for as long as able, up to 5 minutes.