Itsuki-kun ga Osewa ni Narimasu

Chronological release order:

1. Itsuki-kun ga Osewa ni Narimasu:
   Itsuki learns a lot of new useful life skills thanks to his role models, Umi and Riku.

1.1) Shuiro ni Yokujou

1.2) Futago-kun no Seitsuu Jijou

2. Itsuki-kun no Kimochi:
   The story is about the two twins, Umi and Riku, who will have a lot fun with their little friend Itsuki once again!