Lion dancing is a tradition in Chinese culture that I've decided to learn. I've found that my forearms aren't quite strong enough to create the effect of the lion shaking its head. I'm right-handed, so the thumb and forefinger on my left hand holds the bar while the other three fingers hold the mouth closed/let it fall open. My right hand holds the other bar, both of which are diagonal, with my palm facing me. There are various angles that I have to hold the head in, such as diagonally above me to the front, then bending the left and right arms respectively (when one arm is bent the other is thrust forward abruptly and straightened). I don't always have access to the head to practice with; what muscles should I train and how should I train them in order to be able to control the head better? Please note that I am a teen so I might not be able to do certain exercises that adults can.
The picture attached shows how the head is held up. It's from the NY Times.