Self myofascial release of the gluteus maximus oftentimes will decrease pain into the sacral area. The musculotendinous origin of this muscle is very short and resides at the top portion of the iliac crest and lateral borders of the sacrum.
Skip to the 4:15 mark here for a video demonstration.
Although you can have tendonitis of the glute max at the femoral attachment, it's much more common at the origin.
Get a lacrosse or baseball.
Don't go till the point of bruising.
There should be no numbness or tingling created.
Move the joints above and below the balls contact for added benefit.