took me a second to figure out but i’m pretty sure it’s because he called eusan’s name. he usually refers to him as sunbae, which is his respectable title and calling him by his first name would probably be considered rude or impolite considering their ages and whatnot, (they’re also not superrrr close and ian is the younger one) which he knows, which is why he believes he said something mean.

wait I’m confused why was ian so embarrassed