Basically you don't move your avatar at all. When you take a shot, you click and drag the aim marker, the arrowhead with the distance inside it. When you do this normally, your avatar will not appear to change stance, but a radical move will turn the avatar about face 180 degrees.
However, the position of the avatar has no bearing other than cosmetically speaking, so the aim marker is what you need to concentrate on. When you are next faced with this shot, and you believe the ball will not clear the bunker face, you need to click and drag the aim marker until the blue line you see displayed while you're holding the aim marker, moves to a suitable angle. This will be where the ball will now travel when you take your shot. Often you only need move it a little to one side or the other, but on occassion you might find that a rearward shot is the only one suitable.
Good luck.
Lizzie xx