From what I understand, while drunk, Joo Yoon hit on Jaekyung, but then forgot, which hurt Jaekyung's feelings, so he started picking on him to get is attentin, and Joo Yoon couldn't figure out why Jaekyung was being so hot and cold with him, but slowly he comes to be interested in Jaekyung, but doesn't understand why, and Jaekyung just wants his attention and doesn't understand why Joo Yoon is only open abut his interest when he's wasted.

wait am i stupid cuz i literally have no idea whats going on