Plastics

Fujimoto Hajime is a third year high school student who has been dating his teacher Nakajima Keigo for the past six months, but he feels they're in a uneven relationship. Hajime's always the one to seduce Nakajima, and even though Nakajima's birthday is coming up he won't let Hajime buy him a present! Has Hajime been mistaken about their relationship this whole time?

(Source: MangaUpdates)