I think Nanjo was testing him. He said you knew it was wrong and you did it anyway. It's a repeat of last time. I honestly think he wanted to give him a chance. Let's be honest, what he did here is rape. You do not have sex with someone who is asleep. That is simply impossible. This was rape.
Nanjo was the one who put Mokyeon's dick back inside when Mokyeon passed out, when Mokyeon is explaining that he was confused how it even happened, Nanjo changes the subject and asks him if he's not going to do it. Nanjo isn't innocent as you think and atp he's just as much of a freak as Mokyeon.
I think Nanjo was testing him. He said you knew it was wrong and you did it anyway. It's a repeat of last time. I honestly think he wanted to give him a chance. Let's be honest, what he did here is rape. You do not have sex with someone who is asleep. That is simply impossible. This was rape.