Kyonyuu Seido Kaichou Chijoku no Hakudaku Kuro Tights ~Konna Yatsu no Okazu ni Naru nante!~

With a game title that translates as "the big-breasted student council (sex slave) president" ("seido" is a pun on "seito", or student), you know what you're getting in this raunchy, smutty eroge that really lives up to the name. Watch as the prim and proper student council president descends into wanton depravity in the company of her blonde friend and enabler. Packs in dozens of fetishes in nonstop hardcore ecchi action, from 3-ways, uniform cosplay, bukkake, toys including wooden practice swords and pens, fellatio, ahe-gao crazed sex faces, group sex, and much, much more.

[from J-List]