This roller stretch is perfect to release tight hips and butt, and also soothe sore knees.
Lie on your right side with roller under right hip, left leg crossed in front, foot flat. Support upper body on right forearm, left hand on hip, with head in line with spine.
Press into left foot and roll down side of leg from just below hip to above knee, stopping when you find a tender point. Hold, release, and repeat. Switch sides.