Rainbow Dash and Rarity have a new favorite spell. Though they didn't understand what exactly it meant by its promises to bring them together when they first cast it, it's become something they can't seem to get enough of. Rarity gets bigger and more sensitive breasts, and Rainbow... well, she gets to be those breasts. It's a sensation like no other for both ponies, but so far they've only done it one way.

That changes with the coming of a Wonderbolts sexy calendar shoot, and a locker room competition that goes on between the mares involved. Whomever ends up with the most popular picture gets to spend two weeks in the Caymare Islands during the team's summer break, and it's a competition Rainbow's determined to win. It would be easy... except for the fact she has the smallest rack on the team.

Good thing there's a spell that increases a mare's chest size, and all it needs is one willing participant...

Contains: Rarity turning into Rainbow Dash's tits, coupled with lactation, mild mind-breaking, and a whole lot of locker room fun.

Art by mrscurlystyles. Editing by SolidFire and LoyalLiar.