A few months ago I was commissioned to paint several Cockatiels and when the client couldn't get a photo of how he wanted his bird to look I asked for the co-operation of my two. I pointed the camera at them and half jokingly asked them to cock their heads and they did. In every single frame. Now when I go take their photo they always pose. This particular day they decided to play a game of showing each other their tongues. They only did it while I was taking photos and I've never seen them do it since.