This exercise focuses on outer portion of the hamstrings (biceps femoris long head and biceps femoris short head). They are located on outside of the back of the thigh.
Place a foam roller just above the knee joint, hands at hips with fingers facing out. To increase compression, cross one leg over the other. To decrease compression, keep the other leg on the ground. Lift the hips off the ground keeping the chest up and shoulders down and back. Lean slightly to the right to place pressure on the outside of the back of the leg. Slowly roll up the lower third of the back of the leg. Hold any tender spots for 30-90 seconds (try to relax and breathe deeply). Slowly roll back down to starting position.
Repeat with left leg.