Udagawachou de Mattete yo.

Momose may be a recluse but he's pretty observant. He's quite sure that the pretty girl that he saw that day on the shopping district was his classmate, Yashiro. And worst of all, Momose finds the crossdressed Yashiro cute. As images of Yashiro and his reasons why continue to plague Momose's mind, he decides to confront Yashiro about it only to be rebuffed. But Momose is nothing but persistent, so Yashiro better brace himself! (Source: Manga Planet)