What the heck is "PUI PUI PUI🎶"? [Animation]

Lui gets annoyed by Chloe's "PUI PUI PUIII" Sakamata Chloe: https://youtube.com/channel/UCIBY1ollUsauvVi4hW4cumw Takane Lui: https://youtube.com/channel/UCs9_O1tRPMQTHQ-N_L6FU2g Source Clip from: https://youtu.be/sRptjOpPhrI