So let me clarify -if this has a web novel, I haven’t read it I’m just clarifying what happened in the webcomic
it’s not that Jin aroused Gunwu, it’s that touch CAN arouse him, it’s like how if your not sexually active certain touches are just touches, while post- they can feel flirtatious/ and remind you of the sexy times one was touched there. Like people become « responsive » and whores like Jin can clooooock it
Ok let’s pull up chapter 42-
We shall now read in between the lines
« SO IT WAS YOU ALL
ALONG.
YOU HAD
ME GOING THERE-
WITH THAT FAKE
VIBE YOU WERE
GIVING OFF »
Jin then leans in to do a vibe check lol
Then -Feigning concern over his body, is just an excuse to touch Gunwu
The way he’s touching him is intimate, it’s been a while since Gunwu has relations with Teo, but if I didn’t miss one, Gunwu was hyper sensitive lol
And Jin is pressing down on these pressure points specifically to gage Gunwu’s reaction, who flinches and trembles because
A) he’s sensitive in new ways and b)he’s afraid after witness Jin use a machine gun lol
« …. LOOKS LIKE YOUR PLAY STYLE HAS CHANGED SINCE THEN. »
play style in reference to sex, since then, meaning back when they were still living with each other, heck I wouldn’t be surprised if Jin dragged Gunwu around parties and introduced potential matches, or like when Jin went for hook ups, so would Gunwu.
Reminder that At this point Gunwu is breathless not from arousal but really from that fucking sprint to the moving vehicle and being in a high pressure situation.
The stakes are high and thats why Gunwu is letting Jin touch him without pushback because, emotionally he’s wanted to reunite with his brother but intellectually- he knows his brother is genuinely dangerous.
Gunwu is worried that Jin holds a grudge against him.
Hence why he asks if Jin is here for revenge.
But just as Gunwu knows Jin, Jin knows Gunwu, he knows that it’s not just fear causing Gunwu to tremble, but the guilt of a pure hearted kid who had to leave his brother behind for dead.
Jin knows that Gunwu’s good heart hasn’t changed.
When Gunwu cries as he listen to Jim’s ramblings, it’s just all those pent up emotions being pulled out by fear, fear of resentment, fear of abandonment, fear of his brother.
Because what is a tearful reunion is marked by the gun in Jin’s hand,
« Don’t be scared » when there’s a glock caressing your face can’t help but come across as a warning.
But the fact that he presses the gun into Gunwu’s hand to also caress Jin’s own cheek, - fuck he’s just enjoying that violent intimacy. ( I had to rédigeâtes this scene lol )
But Gunwu takes it personally, as failure on his part, he senses that their relationship may have past a breaking point, simply with the clue of « only family » because of the fact Gunwu probably held affection for the old crew members that Jin killed for misplaced vengeance reasons, (if you remember one of which had gone straight and was a young father) and more importantly now Gunwu has Teo in his heart. He knows for a fact that the brothers cant go back to the way things were.
Because what Gunwu wanted even before losing his brother was out of the crime scene. He wanted to live a simple life where he can keep his hands clean.
But Jin wants to drag him back into a mess and literally is putting a dirty gun in Gunwu’s hands.
Neither brother wants to let the other go, but both of them are on different tracks.

WHY GUNMU WAS SO AROUSED WHEN JIN KISSED AND TOUCHED HIM OMG WHAT ?! HE REACTED AS IF HE HAD BEEN WAITING FOR THIS FOR A LONG TIME !!!! MY GUNMU WTF WAS THAT PLEASE ????? ARE U THAT SENSITIVE OOOOR ???