The video below also illustrates a simple one - minute daily stretching routine8 that can help reduce sciatic pain stemming from an overly tight piriformis muscle in your buttocks. (healthy-holistic-living.com)
Sports massage usually works particularly well for piriformis syndrome. (sportsinjuryclinic.net)
Bear in mind that there can certainly be other causes of piriformis tightening or contraction, however the example just mentioned seems to be the norm in what I've encountered. (robdaquila.com)