I mean, you're not wrong. It's a pun: in Korean, "shhh" is 쉿, "shwit". :) It's like Jennie getting away with aaaaalmost saying "bitch I am solo" (bitch 나는 솔로) by pretending she's saying "I'm a shining solo" (빛나는 솔로) :P Also... they have an It's Live performance. Belle is doing the whistle adlibs. Live. It's crazy.
when they said "this is 5th gen" i was like hmmm i guess that's correct but like then i remembered natty has technically been around since gen3 sheeeesssshhhh just imagine there are universes out there where she COULD have been in fromis9 OR itzy/nmixx if she hadn't left jyp post "from idol school" (never twice dow she was in the same boat the chae sisters were there the "WAY TOO YOUNG" boat) ALSO the clicking sample is snoop's drop it like its hot