Some birds potty train themselves. Some, unfortunately, do this using their water bowls and thus make poop soup. Apparently Quaker Parakeets are known for this. For a chronic soup maker, you may want to get a water bottle, like the kind used for hamsters. Birds that bite for the sake of champing might be better off as a breeder.
Birds go through a nippy stage when they hit puberty.
They're trying to establish their position in the social order. This is natural. It reminds the parrot just who is in charge of the flock. Keep in mind that a tongue to a baby bird is like fingers to a two year old human. The tongue is tactile and the bird uses it to explore its world.