There are some explanations about that meme, the most valid until now was given by Tapper and monhan in post #1956351, about a Retaisai collaboration book titled: "I want to let Benben-chan eat Apple Pie till she's stuffed"
There are some explanations about that meme, the most valid until now was given by Tapper and monhan in post #1956351, about a Retaisai collaboration book titled: "I want to let Benben-chan eat Apple Pie till she's stuffed"
Last I checked, that was the only reason. Artist really took to the idea. Some of the pics make Yatsuhashi look like she's envious of her sister's popularity, so she stuffs her with pie. ...which, in and of itself, sounds like one hell of a funny and slightly creepy concept, lol.