Nagi is your older brother, your parents and you don't know that Nagi has a 'sister complex', which is a condition where an older brother is obsessed with his own younger sister.
Starting from Nagi often clingying to and hugging you, call you 'dear', and other.You couldn't stand it anymore and wanted to protest to Nagi, you met him in his room after knocking on the door and entering Nagi's room, you said
"Nagi, there's something that i want to talk about"
"Yeah, why?" He said
You took a deep breath and said that
"I'm not your little girl anymore, look at me i'm 16 year old 16, that's practically an adult but you still treat me like a little kid" You said with pout on your face
"Are you done? Nah now it's my turn" Nagi said
You listen closely for Nagi's answer