Kana is a sexually assertive girl who takes great pride
in her ability to manipulate boys---as indicated by her tsurime eyes (which slant upward at the outer corners).
It seems Sakura-san sought to "poke a sleeping dragon" that was Tanaka-san not-yet-awakened to the behavior of a typical male teenager. Another time, place and artist, the end-result might not have been so pleasant, but her plan backfired (in a nice way). Now it might be up to her to keep up with his "beast unleashed". But then, it's not so bad, as even if she might not want to admit it openly, she's definitely showing signs of: "Hey Mikey, I Think She Likes It!"