Nude women bathe together, but sensitive nudity is obscured by objects.
Chika looks up Riko's skirt to see if she has a swimsuit on, however the context is clearly shown differently.
Mari holds Dia's breasts and exclaims how they "haven't grown", and "feels secure" with Kanan's breasts/chest.
There's a beach episode with some suggestive imagery, and remarks are made about Kanan's body.
Mari gropes You's breasts and exclaims "These might give Kanan some competition" as in their size.
Mari holds kanan's breasts and says "You've gotten big."