This is a tough question bcs the polycule vibes are extreme with en- lmfaoo. It's almost like I can't pinpoint who'd fuck first bcs everyone has some sort of tension going on.
If it were all 7 of them locked together the first to end up would definitely be hccjek. I've no doubts about that one. It's like they're both waiting to get detained within an enclosed space just so the tension could rise in the air and they could excuse their sexual activity for simply being forced proximity. If given the chance, Hs could literally jump on anyone. I'm convinced he's just waiting for the right moment to pounce. (His first choices would probably be jek and kiki though).
Another duo I think would thrive off of being watched/detained are jekwcn... Are we surprised?
Those freaksters would not give a single fuck. Jek would probably initiate, Won would take the bait easily. It's a very simple dance when it comes to the two of them really, despite them lacking in popularity. I believe you need to be a real freak in order to recognize that puppy and kitty would fuck for days if given the opportunity to. They don't care that the others are watching. Won is feeding the sick thoughts of "sn hyung probably thinks I'm a whore, hs hyung is getting off to this, jy hyung is peeking through his fingers" and jek's are "rk probably wants to be in won's place, sh wonders when he'd ever have the guts to do this, sn is getting off to the idea of won being put in his place."
(They are all insane)
(The next to fuck after this are probably hccki...but that's because kiki has fomo and can't accept that won is being serviced and he isn't. Jealousy? Maybe idk.)