No offense but as a girl, I can't understand her. Why go through all that just to play in the team? There are things more important than a superficial thing like that. Her being an adolescence girl is not really an excuse.
So Tsurara thinks that the only way to please anyone she's crushing on is her body. Looks like her mind was broke by that shitty teacher. Or maybe she's just using him as a cover. Her eyes tell me she's definitely not enjoying this though.