Boku to Kanojo no XXX

A girl and a boy experience each other's lives after a mishap caused by her grandfather, a scientist, swaps their bodies. The girl is described as cute, attractive, and short, but also rude and aggressive. The boy is quiet, thin, and has feelings for the girl. After the switch, the boy is upset by the situation, especially when the girl acts toward him in his new form. He wants to return to his original body, but the girl seems to be enjoying being in his.