[While Yamaguchi successfully avoids choking to death on his own air, Tsukishima only bothers to half-hide the grin on his face.]

Mostly I just wanted to see the look on your face.

[Both because he is in fact a huge tease, although Yamaguchi gets the best friend of effect of the least dickish moments, and because, well. He looks cute, sometimes, getting startled.]

[Sue him.]

Besides, it was a way to pass the time, seeing what weird things people can be into.