Summer's Yukkuri sisters
Story starts with a family invading Anon's house as he's doing homework under the supervision of his eldest sister. They get beaten off by Yukari and Hijiri, with the Reimus falling nonstop through two gaps like Portal, while Hijiri holds up the Marisa with her scroll and beats it up. They finally let the Marisa go while keeping the rest of the family, which have been traumatized.
"The sky is scary..."
"Don't want to fly in the sky..."
Later, Eirin lectures them for not holding back, which somehow ends in the two glomping onto their little brother. Eirin realizes that the Reimu isn't entirely wild, and takes it into her lab.
Backhistory: They live on a mountain, near a clan of yukkuris. During an extermination, Anon's mother found the three bodied yukkuris, who were being abused because they had bodies, and kept them. Later when Anon was born, they thought they would be thrown away because yukkuris can't compete with humans, but the mother just told them 'this is your little brother, so you better take care of him'.
As such, Eirin runs a clinic (typical), while I'm not sure what the other two does.
The Marisa comes back with a Dosu and clan in tow, demanding that the uneasy yukkuri that bullied it to get out so Dosu can punish it. Anon tries to reason at first, but Dosu seems to think that the garden is part of the mountain, so there's nothing wrong with intruding.
After giving a few chances, the family makes their move. Anon disables Dosu by throwing a 3000x sweet jelly into its mouth, rendering it comatose with a sugar high, only able to say 'sweet-sweet' and 'happiness'. Most of the clan gets the 'never-ending fall', especially those that try to run.
Hijiri goes in, hitting the Dosu with an uppercut, then keeping it in the air with her scroll while giving it a nonstop combo, before finally smashing it to the ground onto its yukkuris. This results in paste splattering over the family.
To end things, Eirin injects Dosu and the Marisa that was trying to flee with a special paste mixture. Since the yukkuris' paste contains their memories, what she gives them is a mix that forces them to recognize the mistakes they made. Eirin says she'll let the Marisa meet with its family, and tells it to die regretting its mistakes. As for the Dosu, they leave it to clean up the mess, licking up the bodies of its clan members while apologizing to them.
As they prepare the bath, Anon asks them if they don't feel any reservations about crushing yukkuris, since they're bodied yukkuris.
As one, they tell him that they hate yukkuris, especially those who threaten their precious little brother, since they don't have any worth. Anon thinks he'll never be able to win against his sisters.
Anon tells them the bath is ready, and all three tell him that they should go in together.
They start washing his body, then...
"My, what a magnificent onbashira."
"I-I suppose... I should wash this part after all!?"
"Ah... Nn, Nnn... fua..."
Anon claims they're siblings... so they didn't do anything... okay?