Hizamazuite Ai wo Tou

A world where two sexes exist: Subs, who wants to be a dominated, and Doms, who wants to dominate people. Masami, who works at a sub-only club, is ordered by Yuusei, a transfer student...!?
(Source: Shinshokan, translated)
Note: Contains chapter 2.5 and 1 extra chapter.