Jack sits like that on the stairs too!
Jack has a couple of places that he has claimed. Top of the couch, center cushion of the couch, under the dining room table, on DHs pillow (when he isn't around). Every once in a while he tries to test me by sitting in my spot on the couch, and he gets a little growly and snarky, so I poke him a little bit until he decides to move on his own 🙂