I received a metal juicer shaped like a bird for my birthday and am not sure how to use it. The back part lifts up and has a row of little teeth toward the front, then the juice is supposed to pour out the beak. I tried to use it with a lemon to make chicken piccata, but the lemon kept falling out. I'm guessing I was trying to make it harder than it's supposed to be! Anyone know what I'm talking about and know the proper way to use this thing?