Another thing to do to help him and you would be put him on a fence rail and make him go sideways be pressure and release on either side of the girth (front, back) and then when he's got that down take him off the fence and do the same thing so he has a basis for what you're asking.
I'm not sure a fence rail would work, as it would only block forward motion. He tries to back up.
I agree though: don't simulate the rein.
As for lunging... drag his head up off the ground and make him turn around you on a leadrope by making him move his haunches around you while you're walking toward his shoulder and trying to keep his head behind your shoulder. He'll be confused but as soon as he steps forward and away from you, let him go... and then do it again until he gets what you want.
How do I get him to go away from me though? He just walks next to me, comes towards me if I walk away....If I smack him he'll just stand there with his head high, accepting the "punishment" because he's well-trained enough to know that if I have to jerk on his lead or give him a smack, he did something wrong and this is what he has to do: Stand there
I dunno if that made any sense at all... I'm trying to pull what I remember from what I taught my gelding.
If you're using a round pen, walk right up to him and make him move away from you anyway you can. He doesn't have to be phased by the whip, but he will have to realize that you will smack him as hard as it takes to get him to move if necessary.
I had to literally punch my horse multiple times to get him to understand what I meant by 'get your butt out of my way, please' he was so unphased by everything else I did.