For piriformis syndrome, I usually start with the client prone. I warm up the tissues of the lumbar area, glutes, and legs. Once I am ready to do deeper work, I work the client in the sidelying position. This opens up the area of the rotators nicely. You can use thumbs, fingertips, elbows. Be careful at first to not go in too deep too fast and make sure you are not putting direct pressure on the sciatic nerve. Once I have worked out the glutes and rotators I will work the adductors also. Homework is to stretch the area by placing both feet on the floor. Then place one foot onto the opposite knee (ankle to knee) then lean forward towards the raised, bent knee (opposte knee). The stretch can be done in other ways besides seated. If the person is in a decent amount of discomfort, I have them stretch seated. Otherwise the other versions work fine. Be aware of clients with knee problems since this stretch can cause issues with knees due to the positioning.