Useless trivia of the day, the doujin was inspired by this set of promotional pictures made for different retailers as bonus for buying the entire series with them.
All the main characters got one dressed as different animals: Mirei got a dog costume, Mamori a cat, Lady Lady got bunnies, Charlote a doe, Meifong a sheep, Kasumi a wolf and obviously, Akira got a Tiger (that was the bonus for Toroana) and Torino a cow. This pic was also inspired by that set.