Bring a dressage whip when you feed him. If he so much as looks at you the wrong way, correct the behaviour with the whip. If you get your point across, then he will respect your space. This situation can quickly escalate into food aggression, so its best to get after him hard now.
*just realized that this is happening In a stall.. So get after him by making loud noises the second he acts up (shake rocks in a can, scream like a hooligan, growl, whatever you want) and do not feed him until he stands still. Once he gets the point, increase the time that he must stand patiently until he gets his reward (food)