One thing you must not do is put sam down when he bites. If you do he will keep doing it knowing he gets his way.
One way I stopped my babies, was, when they were perched on my hand, if they went to bite I would jerk my hand down, making them put there wings out and let go to gain balance, and saying "NO" in a loud voice, I would keep doing it until the didn't try to bite anymore.
Sam is probably just bluffing.
If you go to get him to step up and he lunges, push right past his lunge and forcefully but carefully MAKE him step up.
Show him who is boss.
My husband will grab their beak and hold it and say "NO". That is something they really don't like and it shows them he is the Boss.
Angie --------- Hatred stirs up strife, But love covers all sins. {Pro 10:12} ----------- God Bless