I agree with you... I am really feeling bad for Jinwoo like his initial situation is not really that good and then it got worse because of that seme....
Aside from Jinwoo kicking the statue... He has no another fault in the flow of the story... He is having lewd visions of himself and he cannot even control it, he tried but because howof extreme they were, he cannot resist it...
It was the seme who helped or took advantage of Jinwoo being horny and the seme actually no reason to hold back why? He is a sadist and a bully... So the sexual acts are not cheating but just to calm Jinwoo.... Does Jinwoo intended it??? HELL NO!
That is why I pray that Jinwoo would have a better treatment or he could just get away from Sangtae... but no.... arrgg...
Actually, Sangtae really was just going to help Jinwoo out. If you go back, you'll see that Jinwoo was the one who rubby-dub-dubbed his booty against Sangtae's erection. Jinwoo knew what he was doing, he smirked in the next panel. Sangtae wasn't going to join in but Jinwoo did that, so he did. Jinwoo was okay with it. At the end when they kissed, Jinwoo was the one who kissed Sangtae first. That mean he consented to this, or at least was okay with it. Sangtae didn't even put it in, that shows that he wasn't entirely taken over by lust.
Spoilers....
...
....
In the next chapter, they only rubbed lightsabers. Sangtae doesn't put it in. Jinwoo did freak out after probably like "omg i can't believe we did that" (idk for sure tho, I don't know korean) but Sangtae does help Jinwoo out. Like they had meeting and sat side by side, Sangtae held Jinwoo's hand to stop the fantasies from happening. Sangtae gave Jinwoo a period pad so he doesn't mess up his underpants when his releases his manly fluid during work. Sangtae obviously cares for Jinwoo.
Okay, i'll break down the chapter for you:
First, you mentioned how on ch 10, pg 28 he pushes his ass on Sangtae's erection and smiles, but you saying it like that is really deceptive. He did that with his eyes GLAZED OVER after having been fondled while under an aphrodisiac like effect... With that out of the way, let's look at the events LEADING UP TO that.
On ch 10, pg 9 he says "i came to beg you to stop the fantasies", on ch 10, pg 22 you can see for yourself Sangtae getting horny while Jinwoo describes his situation (in the few pages before 22) and suddenly grabbing a startled Jinwoo while panting and blushing (Jinwoo says "W-what are you doing!" here and protests the whole time after, the ENTIRE sex scene) before saying "in that case i'll help you out" while looking away as it's obvious even to him it's an excuse to relieve himself (seriously, look here, he looks away while panting/blushing while he's saying he'll "help" and you expect me to believe he's not just horny?), on ch 10, pg 23 you see Sangtae suddenly pull Jinwoo's pants down without permission which results in Jinwoo saying "WHOA! ARE YOU CRAZY!" (another protest) on pg 24 before he comments on Jinwoo's size and starts to fondle him, on ch 10, pg 25 you see Jinwoo say "h-hey wait a min--! Son-of-a... You said i was wrong, but you really are... A gay pervert!" while saying in his head that he hasn't been touched in a while so it feels good (a physical reaction, as i said, he's outwardly saying stop while acknowledging that he can't help but feel good), on ch 10, pg 26 you see him say "bullshit! There's no way..." when Sangtae points out he's getting harder and asks if he's actually enjoying it (classic rapist sentence to manipulate their victim into thinking they wanted it so it wasn't rape), on ch 10, pg 29 Jinwoo asks "w-why are you doing this" (STILL trying to fight off the effects of the fantasies, but you can see that his eyes have been starting to glaze over for a bit now), on ch 10, pg 30 Jinwoo makes it very clear he doesn't want his thighs fucked when Sangtae says to put them together and he yells "WHAT?!". And then the rest is just Sangtae fucking his thighs till they both cum.
Also, on ch 10, pg 36 Jinwoo says himself "i-i told you to stop. The fantasies stop when you touch me, is what i was trying to say", in other words he didn't even need "help" and was trying to say that, but Sangtae got horny and sexually assaulted him which resulted in him PHYSICALLY (not emotionally, he protested the entire time) feeling too good to finish what he was saying. Like, he literally couldn't speak. It's shown how the fantasies cripple him multiple times, he always ends up HAVING to masturbate before he can function again. It's a major case of blue balls. Now, Jinwoo JUST told him that "the fantasies stop when you touch me", which means Sangtae KNOWS he can stop them by just touching him, but in ch 11 he purposely watches Jinwoo squirm on the train and then in ch 12 pulls him into a restroom stall and sexually assaults him again. Still think he's trying to "help" as opposed to taking advantage of Jinwoo's literal INABILITY to not be horny around him when he could've just put a hand on his shoulder on the train to help?
Yeah, I agree Sangtae isn't 100% a good guy. He has bad intentions, he's a sadist, that's been established. But think about it this way; on the train, at work it would be odd for the two of them to walk in holding hands. Not sure if the universe in this manhwa allows open gay relationships but even then two coworkers who barely get along suddenly showing up all close is weird so of course they can't be open and hold hands all the time. So it's done in secret.
In chapter 10, you basically ignored a lot of the thoughts Jinwoo had so let me add them:
-"This feels ridiculously gooooood!"
-"Why'd he have to focus on the tip so much?! All this precum is starting to get embarrassing." (Of all things, he feels EMBARRASSED about his PRECUM. Wow.)
-(when he rubbed his ass on Sangtae)"Take that, then!"
-(After Sangtae told him to wait)"Why? You've already touched me all over!" (He basically teased Sangtae. You can't deny that Jinwoo's is also at fault here.)
-"Wow. His hot breath. It must be getting hard for him to hold back."
-"It's a strange feeling. He's usually so carefree that it's annoying." (Then goes on to how Sangtae calls his name in a nervous voice which he never heard before.)
Let's go back to before this happened, same chapter. But this time put yourself in Sangtae's shoes. Horny dude comes up at your door mad because he can see your sexual fantasies. Sangtae acts appropriately, suggesting Jinwoo needs to go to the hospital and get checked out. Sangtae literally had no idea about what was happening until now. We all know that Sangtae is a pervert which has been established, okay, we get it. So how the heck does he respond to Jinwoo saying:
"When I'm with you, all I think about is sex, sex... And more sex. I'm hard all day long."
Oh, then Jinwoo freaking flashes his sword so Sangtae can see all it's glow-stick glory. Like he went to the extreme. Honestly, both are at fault here. Jinwoo could have done a better job of explaining that didn't involve flashing.
Sangtae suggests masturbation, Jinwoo says that be can't do that wherever or whenever. Which is why in one chapter Sangtae gives Jinwoo a pad so that Jinwoo doesn't get blue balls. So now, Jinwoo can just cum in his pants when he needs to.
As for the "eyes glazing over" that's pretty common when you have sex you kind of lose yourself by lust, Jinwoo was feeling the lust, Sangtae also. You can tell Jinwoo liked it, or at least that he wasn't entirely against it. You can also say that it's something that he got caught up in the moment with and wasn't thinking clearly, which isn't that uncommon to have accidental "sex". If he didn't want it, you would think that he would struggle a bit more, no? And if Jinwoo did make it very clear that he didn't want it, or that he felt that it was rape, I would expect screams, sobbing, maybe him pushing Sangtae away, dramatic coloring, thoughts emphasizing that he does not want it, something more than just a bunch of "Ahh!" "Hng!" And tiny hearts everywhere. We know Jinwoo is strong enough to defend himself, he slapped Sangtae, he yanked himself out of Sangtae's grasp earlier in the chapter when Sangtae was about to drag him to the hospital.
But whatever, if you think that way about Sangtae I understand your view but I'll keep my thoughts as well. Sangtae isn't perfect, but neither is Jinwoo.
No, you're reaching... Like, a lot. On everything you said in that last response... It's not me "ignoring bits", you're the one taking everything out of context in a very sad attempt (Sad because your evidence is weak, not because you think he was consenting. If you'd actually provided a valid argument with evidence that was actually within context, i would've been open to being swayed, but your evidence doesn't back anything you say if you actually read through the chapter and comprehend the flow of events) to make it look like Jinwoo was at all consenting... Yeah, he says all those things, i wasn't "ignoring" them, i put the pages there so you and anyone else could read them... What you're ignoring is the context in which he said those things... Again, it's shown multiple times that the fantasies literally incapacitate Jinwoo, he said those things after having been so turned on by the constant fantasies that he was oozing out precum from just a little fondling... He was already hard and panting/blushing when he got there... He said those things with his eyes glazing over... No, you saying "well, when people feel good their eyes glaze over" isn't a valid counter to me bringing this up. I wasn't saying he wasn't turned on, i was saying he couldn't help being turned on and didn't want what was happening. In other words, yes he felt good, but it wasn't consensual. You can look at this the same as being drugged with an aphrodisiac. You tell me to put myself in Sangtae's shoes, put yourself in Jinwoo's. Hopefully you aren't BI so that you can actually put yourself in this situation. He's straight, if he weren't cursed he'd never have had any gay experiences like this aside from maybe accidents. I don't know about you, but I'M a gay man and the thought of being forced to see and feel some chick's sexual fantasies about me literally disgusts me. Like, no joke. And i imagine it's the same to a straight guy being forced to see and feel himself getting fucked by a man. I literally just gave you multiple protests and him saying "i-i told you to stop". Not sure what else you need. I'm not going to respect an opinion with no logic that ignores reality.
I was saving this as a bit of a trump card, but i guess now works. Jinwoo HIMSELF even says he doesn't believe Sangtae was just trying to help. Look at ch 10, pg 36 where Sangtae responds to Jinwoo saying "I-i told you to stop. The fantasies stop when you touch me, is what i was trying to say" by saying "Oh... Is that right? Sorry... I would've finished sooner if i knew... " (clearly comes across as a lie tbh, too many pauses there). Jinwoo replies with "bullshit". He's literally saying that Sangtae wasn't trying to help him, that it was just Sangtae taking advantage because he was horny. You read the same things i did and STILL argued that Sangtae was "just trying to help"... You're delusional. Like, you basically ignored this ENTIRE chapter.
Who said anything about "holding hands on the train/while going into work"? I didn't. I said he could've "put his hand on his shoulder", but you'll just make shit up for your argument. A hand on someone's shoulder, especially male to male, isn't viewed as intimate. You also talk about Jinwoo flashing Sangtae, again, context is key here. Jinwoo had already told him about the sex fantasies, but Sangtae didn't believe him and tried to take him to the hospital, he only did that to prove it... How do you prove you're "constantly horny because you're constantly being forced to watch something akin to a porn loop in your head"? By showing the results. "Look, my dick is constantly hard, there's proof.", instead of Sangtae JUST taking it as proof he gets all horny while looking at Jinwoo and decides to take advantage, that isn't Jinwoo's fault. By that logic, any doctor has the right to have sex with you since you're whipping out your dick for them... (Also, here's that scene you were mentioning out of context, notice how at this point Sangtae has yet to sexually assault Jinwoo and until he does Jinwoo is able to keep a certain level of coherency as well as strength? Enough to shake Sangtae off, here BEFORE he's being groped while already horny? His eyes don't glaze over either. Then all the sudden Sangtae pulls his pants down and immediately starts fondling his dick before he can react. You see what happens AFTER the sexual assault starts? How he isn't able to talk so much, his eyes start to glaze over and despite literally every word that comes out of his mouth being a protest, all he can do is let it happen? It's almost like he's so turned on by the sexual fantasies and now the actual touches after he "hasn't been touched in a while" that his body wont do what he wants it to. You know, like in literally EVERY other scene where this happened? Remember when he had to leave work numerous times because he couldn't physically take the fantasies and still function)?

Why do some people seem to act like Jinwoo is AT ALL to blame for any of this? People are saying he's "cheating on his gf"... What? He has never consented to being touched by Sangtae, he's actually done the opposite and protested it. Jinwoo is just so caught up in the fantasies that he can't help but feel good when he's touched and he lacks the physical strength to escape. He isn't "cheating", he's being sexually assaulted (Looks like full on rape next chapter, though someone says it just LOOKS like there is penetration), he just handles it really well... or at least it seems like he does because the manga always portrays the scenes in a comedic light. It's the equivalent of saying someone drugged with an aphrodisiac is consenting to sex even if they say no because they're turned on. It's just a physical reaction. Why should Jinwoo have to tell ANYONE (aside from maybe the police, but he looks like he enjoys it when it happens so it might be hard to prove it's sexual assault/rape) about him being sexually assaulted/raped? It has nothing to do with his GF aside from if he wants someone to lean on.