Koisuru Ryuu no Shima
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" appears. After being abducted by a tall, white-haired man with overwhelming pressure named Byakuya (he seems to be a legendary dragon that has lived since ancient times), in no time, he is stripped of his clothes and has sex that blows his mind. With his sister's medical expenses as the condition, Nishino is kept by Byakuya, which makes his repulsion grow. However, seeing the usually cold Byakuya become lustful and enraptured by him during sex, Nishino's heart starts fluttering...?!
(Source: Taiyo Tosho, translated)
Note: Contains two extras.