A lot of patience and work.
It's better to work with positive experiences and R+.
Maybe he/she doesn't like to lounge because it's something stressfull for him/her, so a good point to start it's to let him/her know that isn't something to worry about, to do like a game.
You can start with cone exercises from the ground, for example: you stop your pony in front of a cone that is a little bit far from you and if it's correct, you give the treats.
There are a lot of exercises you can do to work with fun on respecting your personal space and lounging.
(Sorry for my bad english, I'm italian)
beating up my horse wont make him respect me 💀💀
If you want your horse to respect you, you need to do something about it. If you don't, by all means enjoy your horse the way it is.
We dont have round pens at my stables and Clinton anderson isn’t a very good horse trainer.
I would put him in a round pen and free lunge. Look up Clinton Andersons lunging for respect videos.