Kare no Shousou to Koi ni Tsuite

"Seeing what it's like to fall for you wouldn't be so bad."
Yajima usually only goes for older men. One day, though, he meets the younger Kazumi. His not being Yajima's type doesn't stop them from sharing an unforgettable night of passion. After that, Yajima can't help wanting to make things more intense...
(Source: Renta!)
Note: Includes the prequel one-shot "Kedamono Kareshi!".