18+ Saimin, Suki desu yo ne? Idol Datte Hatsujou Sasemasu

The protagonist finds a dvd where a guy called Mr. Zow explains a method to use a powerful hypnotism.
Using it, the protagonist will be able to get the idol that is his classmate as his girlfriend.
In fact, he won't stop there, there are more girls and idols out there after all.

(Source: VNDB)