Have you tried carrying a tiny bottle of bitter apple/orange with you while playing and spraying it on his gums when he bites?
It also sounds like he needs some chew toys and when you catch him chewing on something he shouldn't, replace it and praise him for chewing on the appropriate toy.
It also sounds like he needs some chew toys and when you catch him chewing on something he shouldn't, replace it and praise him for chewing on the appropriate toy.
