Based on the title picture, description and genre, I was under the impression that this was going to be a lighthearted story where a guy goes through some playful bullying/teasing from a girl that likes him but is too embarrassed to admit it, but that wasn’t it at all.
In reality, the main girl doesn’t give a shit about him at that point in time and abuses him both verbally and physically for years, starting from when they were freshmen and all throughout high school.
She’s a superficial thot who sleeps with tons of guys (several different each week) and only starts getting somewhat interested in the protagonist once she learns he has a big dick.
That leads to her raping him early on in the story and then essentially blackmailing him into becoming her sex slave, going as far as to forbid him from masturbating and seeing other girls. At the same time, she herself is still going on dates and sleeping around with other guys.
After a while, she starts warming up to the protagonist and even act endearing at times, but she still calls him names (mostly “loser” or “dildo”, because that’s all she saw him as for a long while) throughout most of the story and at no point does she ever give even a semblance of an apology to the protagonist for tormenting him all those years.
Both the main girl and almost all the other girls just treat the protagonist like an object, caring only about the size of his dick and having sex with him while still sleeping with other guys on the side.
There’s only one decent girl in the whole manhwa who actually cares about the protagonist as a person rather than wanting to just use him to fulfill their lust.
In the best of worlds, the story would end with them together, but instead it turns into some awkward harem ending. I generally like harem endings but this one felt forced and unsatisfying.
None of the girls who treated the protagonist like garbage before ever see any consequences to their actions, and the protagonist himself gets a really strange personality change in the last 20-or-so chapters, basically turning into an unempathetic douche out of nowhere.
I would have much preferred an ending where the protagonist eventually ditches all the thots and forges a future together with that one good girl.