A lumbar support pillow is a type of pillow that is designed to provide support for the lower back. These pillows are typically placed behind the lower back when sitting or lying down, and they can help to alleviate pain and improve posture. A lumbar support pillow is a small, rectangular pillow that is placed in the small of your back for added support. It helps to take the pressure off of your spine and relieves pain in the lower back region.