A four inch ball is used to facilitate releasing the piriformis (butt) muscle. Lie on your back with your knees bent. Place the ball under your buttocks.
Softening into the ball is the most important step in this technique. Start by imagining the top of your feet sinking toward the table. Then imagine your knees and thigh muscles softening/sinking toward the table. At this point you will probably notice that you have sunk further into the 4 inch ball. Now allow the front of your pelvis to melt toward the table. Continue to sink onto the ball for 3-5 minutes, or as directed by your therapist.
If anything seems like too much pressure or pain, move to another area or stop to consult
with your therapist.
After a few sessions of releasing the buttocks you can try the advanced option. Start as
above and after a few releases, grasp the back of your knee region (use a towel or strap if
you have decreased flexibility) and start to pull your knee toward your chest. When you feel discomfort or a snag (restriction) stop and hold for release (softening). Allow knee/leg to move and unwind naturally.