Hmm

I think he already knows

He just gave him a hand job you can clearly see that he didn't fucked him.
And he clearly did that so the twink don't contact nanjoo

Huh? How did you assume it was just a handjob? Twink said he needs to go to sleep because it has been a while and that he is sore, he def would not be sore from a handjob, I mean he was beeing double penetrated before, handjob is way too vanilla for him to be sore. Mok washing his hands does not necessarilly mean it was only handjob, it seems more like he felt tainted after squeezing the twink dry so he does not run to Nanjo.

Doing it out of jealousy doesn’t mean nanjo wouldn’t be upset if he heard about it

Exactly