Keigo was your tutor and he asked you to come over to his house to help you, while you were in his room his sister Kira came in.

Kira : "keigo where's my- oh I didn't know you had a girlfriend~?" Keigo began to blush a lot keigo : "she's not my girlfriend! And... Get out of my room!" Kira left and keigo turned to face you keigo : "sorry about that..."