Toshiue no Kanojo

Shou is a first-year who often helps out at the student council, which earned him the nickname "little helper." He hates it because he feels like it's also mocking his girlfriend, the student council president, Mizuki. However, when she calls him cute, too, he decides that he'd like to be the one in charge for once, and so he makes Mizuki give him a boobjob, never mind that she usually does that for him anyway.