This is just my speculation, but I think it's not Woojin having seggs with Junghwi but the Minhyuk guy.
First, looking at the panel where they were leaving the cafe, Woojin was wearing a white shirt and BLACK pants while Minhyuk was also wearing a white shirt but wearing a GRAYISH pants. Notice on when Woohyeon went to Junghwi's place, it was a white shirt and a grayish pants scattered on the floor, so most probably it was Minhyuk.
Second, knowing Woojin's capabiliy to hypnotize people, I just know he can do it to both people at the same time, so maybe he hypnotized Junghwi Sunbae and that Mingyuk guy into doing the deed.
Lastly, I don't think Woojin has the guts tohave seggs with Junghwi Sunbae HAHAHA
Hi. You've got an eye for details. That made me check the panels. I'm guessing it is the Minhyuk guy too that's doing it with Junghwi.
Minhyuk guy was wearing a white shirt underneath that blue jacket. And he's wearing a grayish shorts because I saw bare legs of a person seated beside Wooyeon, assuming that's him. Last panel showed the guy wearing a sort of long white socks. I ain't a stylist but I think shorts with long white socks come in pair.
Anyways ... this is so efffed up.
As someone who reads BL, bruh both of you talking with all of this shining shimmering glowing background hmmmm sus HAHAHAHAHA
My fujoshi heart skipped a beat