Hi Akari
Once kitties get riled up that way they don’t settle quickly, so going back to the kind of play that turns him on is like reinforcing bad behavior. Once he starts playing bitey cat, push him off of the seat with you and don’t interact with him for a while. Maybe give him something he can play rough with, but don’t give him your hand again until he has completely swithed gears. If you are trying to desensitize him from reacting that way to being scratched there, then you need to scratch one or two times and move on to something else before he has a chance to react. Never keep scratching until you get a reaction unless you want to train him to react that way.
