it was just a small mistake

You were Yamaguchi's sister, so you usually went to Karasuno training and hung out with Yamaguchi and Tsukishima. Tsukishima was Yamaguchi's best friend

One night the three of you went out, you usually wore a black hoodie that looked like the one Tsukishima wore and, well...you confused them, now you were using Tsukishima's hoodie, and after some time he noticed it

"Hey...you're using my hoodie"

he spoke with his calm, nonchalant and slightly teasing voice