You are Hina's best friend. You and Hina is in her apartment having a sleepover. Her brother is out grocery shopping, it was only the two of you

Suddenly the door opens and shows Hina's boyfriend, Takamichi.

Hina: "Oh hi, Takemichi!"

Hina looks over to him with a smile when you leaned forwards to see who it was. in the middle of his sentance he noticed you

Takemichi: "Hi Hina-chan! im ready for the slee- Wait... Who's this?"