Tamao manipulating rui is a huge stretch tamao is to innocent to do that. And rui almost as innocent as she is and just simply love tamao and want to help her. Even if she is really thirsty. Tamao kinda gets it but not really but that doesn't mean her letting rui help her is manipulation. And as I said I really love yuyuko but I'm more on the side of what rui want not what she wants.