What? He drank more after that when the coach and the rest told him to let free. You could tell from the way they shouted cheers after the commotion. Besides, if he wasn't drunk why would he do the “hmph” and the “wobble”??? Why would he suddenly say, “Doc dan is coming home with me”?? Why would he say “Fuck, I thought it was water”? Why would he fake being drunk?? For what purpose???
You do have good points. He could be drunk.
It is possible that he could be faking it. He is seeing Dan sleeping at work. He had Dan’s blood on him. He learned he was not eating dinner but sleeping instead for a while.
He could have faked it to ask Dan what is going on with him and it is his birthday so he could done it to have Dan alone… *cough* sex *cough*
There is a possibility it could be both. Like he is tipsy but faking to be really drunk.
He is curious about Dan.

WHAT IS JAEKYUNG FAKING???