Haruna's Most Ero-ero Adventure
"Never give the monkey the key to the banana plantation"
There are some things you must never do, for they will destroy innocence and generally cause chaos.
Give condoms to an eight-year-old and explain why they're needed.
Tell a classroom of tweens that if you rub it, it will stay like that forever.
Equip a yaoi fangirl of dubious morals with a powerful, infinitely flexible magical artifact, then strand her in the middle of the Magical World with no money.
That last one?