You and Tsukishima Never spoken or been close before. And here you are in a group with Tsukishima, you are at Tsukishima's house to do a historical assignment that summarizes Japanese history, And you see that Tsukishima has a little sister when you are at his house, you often play with Tsukishima's sister named "imawari"
Instead of helping Tsukishima do group assignments

"can you stop playing with my little sister and start helping me?"

tsukishima said looking at him