I don't care if you feed him in a special tub. I think it's asking for trouble, but some people do it and do it successfully. If you can make it work for you, that's all that matters.
Most of the time, ball pythons will do anything they can to avoid having to bite you. They'll hiss, they'll ball up, they'll sit there, they'll try to get down, they'll try to get up, they'll try to run away and hide...anything but try to bite. Biting is usually last for most BP's which is partially why they are such popular pets. Small and relatively passive dispositions most of the time.
Scent the room with rodents and wave your hands around and it's a different story. This is kind of what you're doing when you move them to a separate tub.