Dolls dj - Ruby. Private Dolls

In the Private Dolls series:

V.1 - Private Dolls

V.2 - Ruby
Characters: Sakurazawa+Shouta, Igarashi, Mikami; Shikibu+Toudou, Kashiwabara

From Rootkitten:

1. [...] In this doujinshi naked ape gives their readers an opportunity to look directly into the eyes and heart of the legendary captain.
2. Witnessing a caring attitude of certain members of the 1st unit, Kashiwabara draws quite an unequivocal conclusion.Note: It was released at the same time as the 5th official manga volume.

V.3 - Pillow Talk