(Highschool version. You are Rin's classmate.)

You are walking in the corridor and your hand full of books. Suddenly you see Shidou, Rin and Sae talking and playing in the exit corridor

Shidou hug Sae's back tight Shidou: "Come on Sae! Let's have some fun!"

Sae: "Tch... Lil bro help.." Sae tried to push Shidou away from his back

Rin: "Shidou stop! My big brother has back pain, you know!" Rin tried his best to pull Shidou away from Sae's back