Dukey is still learning about leg yields and side passing so let's say we are legyielding to the left...
So put your right leg on him, your left leg off of him.
Then tighten your right rein a tad bit so that his nose tips more to the right and then put your right rein across his neck to "push" his shoulders over and try to keep your left rein as far from his neck as you can w/o pulling backward.
Eventually you will get to the point where you don't have to tip his head as much.
If you have any questions or that didn't make sense just ask!