Down the Rabbit's Hole by Rikolo
While walking through the woods, Hannah notices an unusual pussy-tree and decides to "interact" with it. As a result, this tree takes her to a magical world.
In this enchanted place, Hannah meets Futanari, dressed up in a rabbit costume. Hannah can't wait to get back and decides to drink a potion offered to her by the Futanari. Unfortunately, things do not go as expected and Hannah begins to shrink.
There is no other potion to reverse this effect, and to remove the spell, Hannah must have an orgasm and cum. The fabulous Futanari is willing to help Hannah with this and provide all of her holes for use.