After backing the horse away from you, invite him to come up to you and the grain. You want the horse to approach with a good attitude. In other words, look for him to approach you willingly with his ears pricked. He shouldn’t have his ears flattened against his head or his teeth barred with an expression on his face that says, “You’d better move or else!”
If he cops that attitude, immediately back him away from you. He’s only allowed in your space and next to the grain when he’s being respectful.
Of course, if your horse has been allowed to get away with a nasty attitude at feeding time for a while, he’s not going to immediately change his attitude and approach you with a pleasant expression on his face. You’re looking for small changes. With repetition, his attitude will improve and he will learn to focus on you instead of getting to the feed.
Continue backing the horse away from the feed and inviting him to come back up to you until he’s doing so with a “Yes, sir” attitude and responding well.