I don't understand what you could not be understanding. Mc says he it's not like he can go ask another guy to fuck him and ml says he doesn't mean that he just wants to get his way but he does mean that he really wouldn't go ask another guy to fuck him and ml knows that so saying he doesn't mean that makes no sense
I still don't understand fully bruh maybe its a me problem but if from what I understood ml (big bear) believes that the line "But it's not like I can ask some other guy to fuck me" is a bit because they already went past this when ml was questioning if mc (black hair) would leave him for a prettier guy and they already made amends before the side stories were released so it is explicitly shown that big bear has assurance and feels secure in their relationship
Maybe I'm not explaining well he says "it's NOT like I can ask some other guy to fuck" me and in the next chapter ml is saying "you were talking about letting another guy fuck you" which was the opposite of what mc had said. I'm now starting to think it's a translation thing. My initial point is that mc says "it's NOT like I can ask some other guy to fuck me" and ml thinks mc doesn't mean that
alright now I get it, so ml says "you were talking about letting another guy fuck you" cause at this point they are technically roleplaying for big bear to be mean to mc to fulfill his desire to have sough rex and mc initially saying "it's not like I can ask some other guy to fuck" is that he did think/talk of another guy which adds a touch of possessiveness given that he mc only mentioned it to provoke, not that he was actually envisioning another man
Daol knows Sangnam wouldn’t actually do it.. That line was basically Sangnam testing Daol’s reaction and trying to provoke him. especially after his coworker flirted with him, plus sangnam’s history of changing partners, he knows bringing up “someone else” will get under daol’s skin. he just wanted to see how daol would react and push him into giving him what he wanted.
you can check the raw directly on bomtoon if you wanna see the original.
"so i don't get why ml thinks mc doesn't mean it when he says he won't ask other guys to fuck him since ml does know that mc would not ask another guy to fuck him"
when big bear thought "he doesn't mean it" means black hair isn't serious about thinking of/fucking another guy because his end goal is to annoy him enough to do it, I think you interpreted it as big bear saying mc actually wants to fuck other people because of the word "not" in the line "it's not like I can let other guys fuck me" and yes the roleplaying was later on but they both knew already that black hair wants rough sex so that's why I said it didn't matter

"But it's not like I can ask some other guy to fuck me" "I know he didn't mean that" "it just shows how badly he wants this"
This is the only bit I didn't get, he didn't mean the rest of what he said it was to provoke ml but this bits true but why does ml think the bit about how he won't ask someone else is the bit he doesn't mean am I missing smt