the main character (a guy) is separate from his older sister at young age cause parent divorce.

when they enter around high school the siblings meet again. the sister became a popular singer

the name of the band that the sister is in is call "Incest"

the story of the manga is toward incest ( the siblings liking each other). One guy in the band also like the sister.

that's all about i can remember

if anyone know the title plz post

tyvm in advance

Seishun pop!
I don't like titles with punctuation at the end.

ah that was fast tyvm really appreciate it. been looking for this one for quite sometime. after onemanga was down i couldnt find it anywhere