What happens when I call your name?

In the Korean comments

The comments turn Jihoon’s reaction to Youngjae into a recurring fan joke. One top comment reads, in translation, “Ah, Youngjae’s male fan is back,” while another imagines Jihoon saying, “It’s Youngjae hyung, whom I like,” and Youngjae thinking, “Cute kid.”

What the words mean

사심 채우다 (sasim chaeuda, literally “to satisfy one’s private feelings”) does not simply mean fulfilling a personal need here. In the teasing comment “Who’s indulging their bias?”, it suggests someone is using the name-calling setup to enjoy an obvious personal favorite.