i always thought it was a good thing when the horses feet & body followed it's nose.
Though if you must do it at the standstill, take his head slower. Oftentimes if you take the head quickly it throws the weight of the horses head and shoulders in the direction you want, so it can't help but rebalance by sending its feet.
If he still moves and you want him to stop just keep him going in small circles. He'll figure out that it's easier to stop than move.
I especially agree with this statement. Horse should follow his nose.
But, it's possible that when you are asking him to flex laterally, and you want him to start this with poll and neck flexion, that he is bracing his neck and just turning his body around , like a swinging gate?
If that is the case, he is either resistant to bending at the neck and poll or doesn't understand that you want him to do this.
Stand on the ground next to him facing forward, at his shoulder. Pick up the rein or lead rope and bring it back and up , as if you were in the saddle and lifting the rein to creat a bend. Put on some soft but steady pressure. If he gives to that, you give back but not all the way. You give back 75%, and then take up the pressure again, 'til he gives/ you give, then again and again until he brings his head around freely, when you give him a huge bunch of slack.
If he boards up his neck, but starts to move his feet to turn toward you, then you maintain your position right next to his shoulder (watch your feet!) and turn with him But DO NOT release the pull on the rein or leadline. Keep a sharp eye on his face, and if he bends toward you with his neck, give release right then, regardless of what his feet are doing. Do this enough and he'll realize that it's the bending of his neck that you want, not the pivoting around.
Eventually, you will WANT him to turn, but only after he has followed the rope with his nose, his face, his neck and then his feet.