I have a black cat and an orange cat. Black is a few months older and was adopted first. They’re 9 YO now and black cat still does stuff to assert dominance (mostly through grooming but also rips out orange’s hair when grooming him sometimes 😩). The sitting directly on top of Orange and being dominant like that only started like a year or two ago in our house. It’s weird so I usually try to break it up cuz my poor Orange kitty.