The Volas Inflatable Lumbar Reliever, Adjustable Air Bag Waist Support Plate to Relieve Lumbar Disc and Waist Stretching Artifact Wholesale listing says perfect for seated and reclined positions.
The page does not name an office chair, a sofa or a mattress. Place the plate where it will not slide, then sit or lie as you normally would. Perfect is listing copy.
Read the Volas lumbar page.