Yes they did. Mingyum clearly said when they were having sex (with chunsam) that he felt nothing but pain when he had sex with that hyung unlike with chunsam he felt good while they're doing it. The uke also include "you don't like second hand man" (something like that) to chunsam (⌒▽⌒)
oh sorry my bad I did not read the side stories. ╥﹏╥
It’s because I’m the beginning the story was more shounen-ai, so it was more implied that they had sex. Later chapters, they added a mature rating and so naturally they added sex scenes
I don't think he did. because he was wearing his clothes when he woke up the day after. And the blonde guy too. Maybe the only made out. Maybe he told the seme that he slept with him to make him forget about him??????