Kyoudai Gokko to Shojo Bitch

Hisaki lives alone with his younger step-brother, Yuzuru, his only remaining family member. Before he realizes it, he starts developing feelings for his brother, who's grown into an attractive young man. Hisaki starts working at a call service for men for the money and to help get over his feelings. His cool, bossy persona makes him the most popular guy at the club. But, he's actually never gone all the way! Just as Hisaki starts worrying that he won't be able to hold his feelings inside any longer, a misunderstanding results in Hisaki and Yuzuru getting it on... It's a hot, steamy love story between two step-brothers.

(Source: Renta!)