Fate/kaleid liner Prisma Illya - Season 3 Episode 3 Girls, Life is Short, So Rot Away

Plagued by thoughts of lewdness surrounding Illya and Kuro, Mimi starts putting her thoughts down into story, which soon turns into a gender-swapped boy's love story. This soon catches the attention of her classmate Suzuka Kurihara and her sister, who decide to use her story for a yaoi doujin. Concerned about Mimi's gradual transformation into a fujoshi, Suzuka asks Illya, Miyu, and Kuro for their help. Despite not being fond of Mimi's fascination with BL, Illya learns that it doesn't mean they can't still be friends.