Koisuru Ryuu no Shima

Koisuru Ryuu no Shima summary:

In front of Nishino, who had graduated from high school and was spending his days with part-time jobs to pay for his sister's treatment, “Destiny” appeared. After being abducted by a tall, white-haired man with overwhelming pressure named Byakuya (seems like he’s a legendary dragon that has been living since ancient times), in no time, he was stripped off his clothes and had sex that blew his mind. With his sister’s medical expenses as the condition, Nishino was being kept by Byakuya, which made his repulsion growing. However, seeing the usually cold Byakuya who become lustful and engrossed toward him during sex, Nishino’s heart starts fluttering…?!