When side bending the spine, both in isolation and in the context of yoga poses, you can focus on the short side of the side bend to make the side bend easier to feel.
Spinal Movements (Part 7) - Yoga Synergy
The Spine and The Core
The Injuries Thread - Page 25
Avoid common pitfalls while bending sideways
Sitting spine side bend
Types of Spine Curvature Disorders - Spine Institute of Arizona
Lying Spinal Lateral Flexion (Side Bends)
Sports Acupuncture Archives - Page 2 of 3 - American Acupuncture Council
Analysing Milo's side-bend video
Motions of the Joints of the Lumbar Spine
Pain in the back: Your child's backpack may not be the cause
Seated Side Bend: Tips and Recommended Variations