little sister Huruka knows why Yuuka is in such a hurry, even if her idiot brother doesn't, he's such a dense, clueless, idiot, and so unsympathetic, fool, he didn't realize when Yuuka was sexualy excited and having an organizime. Huruka could see what was going to happen, she was embarrassed and left the room, and that's why Yuuka was reluctant to have her watch, but both girls love him, thanks.