Spinal rotation occurs at the thoracic/ribcage portion of the spine NOT the low back or lumbar spine. The low back is designed to flex forward and bend backward not to twist. Hanging out all day rotated and sluching in your chair is setting yourself for disc injuries and jamming the facet joints of your spine. I see lots of people with stiff thoracic spines due to bad breathing patterns, a history of rib injuries and shoulder injuries. Do yourself a favor and open up the ribcage portion of back. Learn to rotate from the thoracic spine and keep your low back nice and stable.