How can i get my atiel to stop it's screeming!?

I think he is addicted to millet b/c when i first got him he wouldn't move, eat, drink,or anything. he was extreemly scared of me at first, but i started offering him millet when he was on my finger. Recently he has shown pion towards me and is acting like a normal bird, doing birdy things. Exept when he wants millet. (He only eats the normal birdfood if i mix millet with it). So the loud screaching starts, he paces back and forth infront of his cage and when i open it he seems friendly, but as soon as he is out and on my finger, i get the cold shoulder as he flaps(wings are clipt) towards anyplace he thinks there is millet! (holding it up and feeding lets lots drop on the floor, and it's kinda hard to get it all.) when he cant find any, he jumps ontop of his cage and screams at me for it. I've found that putting him back in the cage with a blanket overtop stops it, but i dont want my birdy to live in darkness.