I put him on my finger, and whenever I said "wings", I would sorta shake my finger up and down a little until he flapped. Then I fed him millet. I chose the word "Wings" because I thought it could easily be used in a sentence, like "Show me your wings!" or "Where are Morpheus's wings?". Because I don't want their tricks to be just a one word command and then they do something. I want it to be like me and the birdie are having a conversation or something. You know?
Anyways, at this point, he still thinks that any time he flaps his wings, weather I say the word or not, that he'll get millet. He also won't do wings if he's sitting anywhere else other than my finger. But we're working on it. We've only been doing it a few days
So after doing it a bunch with wiggling my finger, I would try it every couple of time without wiggling my finger. Eventually he started doing it just from the word. But he still needs a finger wiggle every now and again...especially when he's distracted.
So that's how.