I remember reading some time ago and it was so cute. Anything Natsume Isaku made is this cute ><. Anyway, to read this, go to this link " http://www.mangago.me/read-manga/devils_honey/uu/devils_honey-chapter-1/ ".
ok so summary is this. There's this phys ed teacher who was assigned by the principal to monitor a gang of delinquents. However, it turns out this gang is just a normal mischievous students. The principal gang was just being biased and not cool.
Also, the head of the delinquent gang met with the phys ed teacher before when he was young and helpless. Phys ed teach changed his mind and his life, so he felt quite strongly towards him. In the end, they date <3
Devils Honey