Mou Hasamazu ni wa Irarenai♥: Hoshi ni Onegai shitara Konnani Okkiku Nacchatta! Special

A regular high school girl's life is turned upside down when Inori collides with Halley, an alien on a mission to observe humans. To fix the damage from the crash, Halley repairs her body — and somewhere in the process, accidentally supercharges her in every way imaginable, including a dramatic increase in her bust size. Now Halley needs to stick around and monitor her as part of his Earth observation mission, which means Inori suddenly has an alien roommate watching her navigate school life, her classmate Sugiuchi, and a body that draws a lot more attention than it used to. The premise is pure sci-fi comedy logic wrapped around adult content — alien interference as the justification for everything that follows. If you've watched Resort Boin or Aneki... My Sweet Elder Sister The Animation and want something with a similar vibe but with a light science fiction twist layered in, this scratches that itch. The human-alien dynamic gives it a slightly different flavor compared to straightforward slice-of-life hentai. This is a one-episode special bundled with the DVD release of the main series from studio Peak Hunt, so it's a short add-on rather than a standalone story. Going in having seen the main release will give you more context for who these characters are and why their dynamic works the way it does. Short, straightforward, and exactly what it says it is.