I think the way Hyuk is always up in Joowon's personal space is so telling when it comes to their relationship. Han Joowon with his rigid boundaries on being touched and Hyuk who must be Very aware of this but keeps doing it anyway because he knows he can get away with it. And sometimes it bothers Joowon while other times he just lets it happen lol. It screams "I don't like when people do this and I might glare at you for it but I'm also not gonna actively stop you because I guess it's not so bad if it's you" and so Hyuk is always testing how much he can push those boundaries. And then just like with Dongsik there's of course that aspect where Jowoon is like "no touchy >:(" and then proceeds not to keep his own hands off Hyuk in return. It's great