If you have a foam roller this can be a great tool.
While seated on the floor with a foam roller positioned directly behind you, lie back onto the foam roller.
Put your hands up by your face. Elevate your pelvis and begin gently rolling back and forth over the roller. If less pressure is desired, this exercise may be performed upright, against a wall. Perform as directed.
Additionally, laying on the foam roller with your tailbone, spine, and head resting on the roller is a great relaxation exercise. Allow your arms fall to the side with elbows touching the ground as you relax on the roller for 1 minute.