Very anatomically correct, transformation, size inadequacy, fisting, shameless sequel hook. 4192 words in 1 chapter.
Anatomically Correct, Centaur, Centauress, Creampie, Dirty little secret, Elf, Elf centaur, F, Female, Fisting, Human, Human/centaur, M, M/F, Magic, Male, Male/Female, Potion, Size Difference, Size inadequacy, Story, Vaginal, Vaginal Penetration, Yiff, dirty, little, secret