I misread this at first, thought you were doing yoga with a sofa. Glad your hip and back are improving!
Actually I often do Yoga on my sofa.
Shzivashana is the Sanskrit name.
I was at a yoga retreat a long time where the yogi said, "Do not say you cannot do yoga. There are 225,000 yoga poses. Everything you do is yoga." Yes, including laying on the couch ;-)