Eiken

Everything About Fiction You Never Wanted to Know.

Eiken (rhymes with "achin'[1] -- erm, taken") is an 18-volume manga series and two-episode OVA by Seiji Matsuyama, where a dorky kid named Densuke gets dropped into a school full of large-breasted girls vying for his attention...but he just wants the eyes of the "cutest girl in school", Chiharu. Hilarity and extremely suggestive hijinks ensue as Kirika Misono, a Hot Amazon / Jerkass / High School Hustler, shanghais both of them into her private fiefdom, the Eiken club, to serve as her Butt Monkeys. At least this means Densuke has an excuse to talk to Chiharu now...

Long story short, this could be simply Seiji Matsuyama testing how much he could get away with.

Eiken is most well known in the West for its OVA, although it's a loose adaptation that hardly covers the original manga at all.

The Eiken manga and OVA contain examples of:
  1. "I have no idea what that name means, unless it's a reference to how most of the female members' backs must feel"
    —Dave Watson, Being Upfront‍'‍s capsule description of Eiken