Gakuran Virgin

Mikami Keichi had always lusted after  Tachibana  Yui, the class president.  But someone like Yui was as untouchable as the moon for a deliquent Mikami Keichi, until Yui appeared one day in the old class building, where Keichi and several other students operated a prostition ring.  Yui needed money to leave home, and he was willing to do anything for it, including letting Keichi train him to be a prostitute and pimping him.  But either counted on falling in love. 

Also included, Kiss and Poison, a perverse story of a young boy trained by his elder brother to be his sex slave.  This is an extremly explicit manga.