BLT: Burning Love Twin (2006)

Nozumu goes to a tough all-boy’s high school while his identical twin Saku attends a prestigious co-ed institution. Nozumu suspects that one of Saku’s male teachers wants to seduce his precious brother and convinces Saku to switch schools and identities with him for a day, using the pretense that he likes someone at Saku’s school. Nozumu was right about the teacher, and takes care of the situation, but little did he know his best friend Youji would fall in love with Saku or that the sports sensei at Nozumu’s school has his eye on Nozumu.

Source: www.anisearch.com/manga/3337