What is Kei to you?
Yo doesn't exactly get what love or dating is. After all, things ended up in a disaster with Mitani, his ex-girlfriend. And for some reason, he feels much more comfortable when he's with Kei. Sure, Kei may look like a girl, but there's something more to him than just his appearance that allures Yo.
And when Kei makes a move on Yo, Yo doesn't stop him. In fact, he might even enjoy it...