SENSEI NO IU KOTO KIKINASAI!

Masaki Tsuji's a 30-something year old high school teacher as sincere as they come. His student, Sohta Izumi, is in love with him. Through many twists and turns, Sohta's earnest feelings eventually swayed Masaki and the two are now in a romantic relationship. Sohta's dating Masaki, something he thought he only could've dreamed of. His fantasies are reigned in by Masaki, who forbids any kind of hanky-panky at school and sex until graduation! Forced to hold back right after attaining his love, Sohta's jealousy builds day by day. Just then, Mr. Noda, the new school nurse, catches on to their relationship...

(Source: Renta!)