party party party ♪•*¨*•.¸¸♬︎

In the Korean comments

One comment focuses on the contrast between Kazuha and Chaewon, reading Kazuha’s expressions as newly relaxed and playfully casting Chaewon as the example she can learn from. It reads, in translation, “Kazuha’s expressions look natural now, as though she has let something go. She’s doing well, with Chaewon there as teaching material.”

What the words mean

내려놓다 (naeryeonota, to set something down) is figurative here: the commenter means Kazuha appears to have let go of her inhibitions. Calling Chaewon a 교보재 (gyobojae, instructional aid) then extends the joke, presenting her expressive performance as a model Kazuha can study; both expressions are casual and playful.