This exercise will improve mobility throughout your spine and hips.
Start by sitting on the ground. Bring your left leg forward with your knee and hip angles positioned at 90 degrees. Bring the right leg behind with your knee and hip angles also positioned at 90 degrees. Position your pelvis and spine upright. Now, using your thigh muscles, press the knee down into the floor and lean forward over the front leg. Take 5 slow deep breaths. Now, rotate to the right, lean forward and take 5 more slow deep breaths. Finally, rotate left, lean forward over the foot and take another 5 deep breaths. During each position change, try pressing down through the thigh/knee as you return to a sitting position. Repeat on the other side.