Here: http://www.mangago.zone/read-manga/ringo_ki_kara_ochiru/
Read chapter 4 for some context (it's a prequel)
Basically Gorou (black hair) is so scared of being alone that he became an attention whore bully and now that he's become isolated the only comfort he gets is the attention crazy psycho-boy (brown hair) gives him. Now psycho-boy is very messed up and he gets off of "breaking" bullies, which is why he ruined Gorou's life, but the fact that Gorou hugs him during sex gives him the impression that he's being accepted despite being a crazy psycho.
Long things short, they both love eachother in a very effed up way but aren't capable of sincerely expressing that although, at the end, psycho-boy does admit he doesn't want to be hated by Gorou and we see that the feeling is mutual because Gorou did keep the cactus picture he gave him.
Voilà.
I actually really like this messed up oneshot...
I DON’T UNDERSTAND A BIT THE VOL.4 CHAP 7
What happened in the last pages?
WHY EVERYONE LOOKED LIKE THEY KILLED SOMEONE LOLOL I DONT UNDERSTANDDD
Please can someone explain. I have questions, A LOT. (/TДT)/