It is Nanjo. No doubt there. Cos how would Mokyeon clean up, strip Nan and put his dick back to his hole while knocked out and unaware?
Honestly I would have doubts if Mok was holding/embracing Nan while sleeping cos other manhwa tops do that like they put it back in then hug their bottom's tight as if to make sure it doesn't slip out but not in this case.
I didn't mean the cleaning up part, that was Nanjo for sure, but I don't think we can exclude that Mokyeon in his sleep got close to Nanjo and his dick got hard again against his ass and he slipped it back in while unconscious. It makes more sense to me than Nanjo putting Mokyeons flaccid dick back inside idk
Could it be that Mokyeon put his dih back in during his sleep without realizing it? I don't get why everyone thinks it was Nanjo