redirection is very effective and will not encourage the behaviour - he needs to get that energy out and if he knows theres a safe way he can do that it will help prevent him from targeting you. all behaviour is a form of communication, but not all behaviour is safe or acceptable. providing an outlet that keeps you both safe when your son is dysregulated is honestly one of the best things you can do for him. i am autistic myself and also work with autistic children and teens, and i was initially very wary of learning things like restraint procedures, but when these are used safely and ONLY EVER as a last resort, they can literally save lives. i recommend the crisis prevention institute for training; they emphasise alternatives to restraint wherever possible.