How Would I Fix this Follow Script?

programming flash
1

If u look at the swf below, im trying to make it so that the head stay on the chars shoulders and follows the moves. If u hit z u can make his tounge come out. Anyone know how to fix this? This is the script im using

onClipEvent (enterFrame) {
_rotation = Math.atan2(_parent._ymouse+_y, _parent._xmouse-_x)*45/Math.PI;
}

2

Moving the point made it follow a little better but would i be able to get it so that the head stays on its shoulders and not rolling backwars n stuff. Look at my file ull know what i mean. I posted the fla too if anyone knows how to fix the problem.