Ai wa Chittomo Raku ja Nai

Jack of all trades, Koga, was sent to Kamiyama's house, as Kamiyama is a famous novelist who hasn't published any new works in years. Koga's first meeting with beautiful, but sharped-tongued and weird Kamiyama was the worst. For some reason, he got picked by him to do the job for the second time. Koga fearfully went to his house and suddenly got asked by Kamiyama to have sex with him?! Also includes the twisted love of Asahina, Kamiyama's friend and editor.

Source: My Anime List