I think the sex scene was unnecessary ;-; He could say It in more innocent, romantic way. ...

But we’ve been deprived of some happy time, so I guess the creator wanted to just give us some vent sex + confession to make up for it ahaha ლ(´ڡ`ლ)

While not necessarily necessary I feel like this scene was not about sex but rather about making love. And while that sounds like the same thing its merely similar as 'making love' can be called 'sex', not all sex could be considered making love. They are at a young vulnerable time in the life when it's not uncommon to mistake biological desires for love and until now I feel we've only seen them act on sexual urges due to heat or hormones. This is the first time where we can clearly see that they are both hurting from the misunderstandings of months apart, neither knowing what to say or do afraid that no matter what comes out it will be wrong, and this is the only way they know to be intimate. Yes, they definitely need to talk to learn to open themselves to each other with the security of knowing that their feelings are valid and that their partner is not going to leave. They're just not there yet.

If I could upvote a comment, I would upvote this one a hundred times. So eloquently said. On my first read of the chapter I felt confused as well (add up my korean language skills, I was confused since the earlier slides they were so kdramaish then boom sex! Lol) but after reading it in english I can see why the sex added up a layer on Dojin and Hyesung's relationship. I mean Hyesung's still confused with his relationship with Dojin and due to childhood trauma, can't really open up well to his feelings even to himself. And to Dojin, though he is very straightforward to telling himself he likes Hyesung, its not easy for him to actually tell the person because of the fear of Hyesung running away but since that already happened Dojin wanted to waste no time in conveying his all his feelings the only way he knows, making love. In conclusion I do think that the sex part is a pleasant surprise. :D

Oo, rightly said ヾ(❀╹◡╹)ﾉ~

Wow, that was deep O.O I hope It's true. I'm still confused cuz for me It didn't look like Hyesung wanted it, but I may be wrong.

That's the awesome thing about artistic expression, we can all interpret something different and all be right about it as well. Maybe Hyesung really didn't want it or maybe he just hates the part of himself that can never refuse Dojin or maybe this is all out of both of their control and they're slaves to being "fated mates". All can still reach the same conclusion yet each of us as readers will experience the story differently.