This will be long...

So, here’s what I think about what this new chapter says about Miyamura and Hori...




For background:
While Hori may not have asked Miyamura or acknowledge this issue with him, it was evident early on that Miyamura was a social outcast. Even when he was young, he was considered gloomy and was excluded from a lot of stuff so he started self-harming through piercing to cope. This ostracized him more so, by high school, he had grown out his hair to try and avoid getting even more negative attention. While he wasn’t as bullied in high school, he was still an outcast until he met Hori, Ishikawa, and Yuki. When he started dating Hori and radically changed his appearance, I don’t think peer pressure was the main reason he cut his hair. He grew his hair out partially to isolate himself but he realized that he had friends who didn’t care about how “gloomy” he was and were willing to defend him. The realization that he had friends who liked him regardless gave him the confidence to stand out more though I imagine he also gave in partially to avoid his friends being ostracized. Now, the recent chapter...
Hori was sensitive enough not to ask Miyamura why he had so many piercings but I think she drew some conclusions that it was linked to when he was depressed. Her anger over him trying to make sure the holes don’t close is because she thinks that means he wants to harm himself again. The fact that he’s not wearing his piercings means he’s not really thinking about his piercings and the emotions that he associates with them. I think this shows an aspect of relationships in Japanese manga where there is an expectation to interpret certains things without talking with the person in question out of a sense of privacy. I think it also reflects how deep their understanding of each other is at this point.
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Hori has shown severe jealously and issues with trust and control because of her belief that she needed to present a certain image of herself at school and her inability to relax since her parents were both frequently gone. I also think this ties into her sadistic tendencies because she is so used to being in control by maintaining a certain distance with people that she can’t in a relationship so all these new emotional experiences cause her to lash out. The fact that Miyamura is the first person she can relax around means she is more willing to vent her feelings (too much at times), to be selfish both in her behavior and her more masochistic requests (plus, Miyamura could never hit anyone but Shindou with a sense of malice), and this leads to her being a bit dependent on Miyamura. Miyamura is also coming from a weird place socially and I think recognizes how much Hori has been struggling up until they met. While Hori needs to work on her violent outbursts, I think they recognize the faults they both have and try to be supportive to one another in their own complex way.
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Also, I think Miyamura is a masochist and Hori is a sadist/masochist, and honestly Miyamura seems more uncomfortable with the idea of hurting Hori than of anything Hori does.
I know this is not everyone’s opinion but i felt like writing this down.