Ayakashizoushi ~Oumagadoki no Yume~

Main character is the successor of a shrine, but he does not believe in monsters, spirits etc. One day youkai begin to sing. Protagonist does not know how to handle youkai, but thanks to that inability he manages to handle them his way - by having intimacy with them. Luckily, all youkai have shape of little girls. Protagonist's revolution has begun!

[From vndbreview]