Sukumizu Uchuujin ga Mina-san ni Otsutae Shitai Koto ga Arimasu!

One day, Kaname Ootawara, an unsuccessful manga artist, rescued a girl in a school swimsuit who was drying out on the side of the road. The little girl, who had to be revived by water, was an alien from the Republic of Breu, a water planet...! The alien Etoile's purpose was to "warn Earth of the crisis that is approaching"! To do that, Etoile and Kaname, with the help of their neighbor Reiko, somehow end up making naughty videos for the video site P-Tube...?

(Source: Gamma Plus, translated)