Zettai Fukujuu ~Houkago no Boku wa Goshujin-sama~

Main character is a sociable young man who helps porn writer Hitomi living next door and thus has a lot of free time. This time Hitomi invites him not to do cleaning or shopping, but to broaden horizons of her imagination with the help of an invited girl Suzuka. Suzuka dreams of becoming a protagonist of a porn novel and being trained accordingly.

[From vndbreview]