UPDATE: Still on the up and up, generally speaking. Charlie seems to be mellowing out a little bit. Usually when he was on my shoulder as soon as I felt that little beak on my ear I would remove him and let him know I didn't appreciate it. However, yesterday I decided to just SEE what his intentions were with my ears all this time.
His intentions, as it turns out, were to be adorable. He gently nibbled my ear all over the place and stuck his whole face inside it at one point. Now I let him get his nibble on, only removing or scolding when it gets too hard. At one point today he held on to the top of my ear with his beak and then gripped the rest of it with his feet. He was gentle, but needles to say I didn't let that continue.
Today he did something a little weird. He knocked his beak on my shoulder a few times like a woodpecker. I have read some "theories" as to what this means, but it seems as though no one knows for certain what this behavior means. Any insight?
Since he does SO well with his clicker and positive reinforcement, I decided to start clicking and treating when it comes to him being touched. It worked to make him see stepping up as a positive thing, so I figured why not. Make him see it as a positive thing and then phase out the clicker aspect and treat less often. So, today I started to just gently cup my hand over him while he was on his perch. Of course, his first instinct is OH MY GOD I HAVE TO BITE THIS THING, which got him a "no," of course. However, when he didn't bite it after touching him a few seconds, he got a click and a seed. After a little while he was moving TO my hand to press himself into it, knowing that he would get something special in return. He would still bite here and there, and I know it'll take some doing to purge him of his default reaction.
It's been a challenge reprogramming this little guy, but with most problems behavior-related, it looks like it's treats to the rescue!