I would've lost myself if Akirara/Akira-kun actually got a mizugi-themed costume later on
LTalon said:
Double check under the dress if there's a swimsuit underneath?
Speaking of, there is a 3rd party fanart of Akirara being dressed in a school swimsuit and then in a beachwear bikini. Same artist (henderas1) also did another art of Mermaid Forme Akirara being tentacled by THE GREAT FOETOPUS (SFW, mostly. She's just being restrained. Definitely Safe by Danbooru standards, but not by workplace ones). Also another art of Kougetsu Shinzou (from Ishiyumi's other series), though that one is NSFW (technically nothing sexual is depicted, but the entire scene is drawn in a highly suggestive manner).
Was tempted to upload one of those, but they have, well... low res, no dialogue, flat shading of colors, bit of anti-aliasing issues/artifacting and some anatomical... oddities, so yeah...
Anyhow, bit of a pity that Ishiyumi's works don't really get much 3rd party fanart. Probably because Twitter being hard to navigate* limiting exposure, maybe.
(*Except for active followers following the latest tweets/art. But if you want to find anything older and aren't lucky enough to stumble into a "moments" list of tweets, whoooo boy...)