A childhood friend has become a famous idol and one thing leads to another.
1. The Sexy, Heart-Pounding Study ~My First Time Was Onii-chan~
2. The Sexy, Heart-Pounding Study ~Mihoshi Is Punikyunyaa!?
3. The Sexy, Heart-Pounding Study ~My First Love Of An Onee-san Is A Gravure Idol~
4. The Sexy, Heart-Pounding Study Ch.4 ~Mitsuki is a Kindergarten Teacher~
4. The Sexy, Heart-Pounding Study Ch.4 ~Taking the Sisters as his Girlfriendsr~