Sumi Takaoka

She has a huge crush on Sudou Mitsuru. Using her father's newly developed growth hormone medicine in hopes of transforming into a flasher, eye-catching woman in order to get Mitsuru to notice her, she instead becomes stuck with the dilemma of changing into a man whenever her heart beats faster and becoming excited near Mitsuru. However, as a man, she is prone to acting "cool" with charisma toward people; therefore attracting a lot of attention; including those of Kyouoko-sensei and Mitsuru. She learns she has to get to know Mitsuru first before knowing what type of girl he likes after he's rejected by Miyo-chan. She supports him as he likes the female Hozumi, but as Hozumi only wants to be friends with Mitsuru after all. She starts to fall for Nishiziwa afterwards, and can't decide between Mitsuru and Shizuka. (source: wikipedia, CUTExGUY)