Well, I think that's because Yukari was talking about other things before she came in, and as soon as she saw the scene she gave an "I got it" face....You must have sense of a football master to understand(or misunderstand? lol) this quickly. Just personal opinion :p
Oh, I get it.Oh, but why?If you work at a girls' high school like I do, you don't see much of the male body...Sto... This is not good!It's all right... I'm prepared to quit if I have to.But I'm not!Hey, Eirin, listen. Just a while ago...You wouldn't see that much even at a mixed school!She's as insightful as Nakamura Shunsuke!Wait...! Please, stop it, Yagokoro-sensei!