I mean if it just falls out on it's own, you'll need to get a new, bigger one anyway and the prince won't find who it fits... Because it no longer does.
There must be a gay Cinderella remake out there somewhere. Grindrella gets visited by the fairy thotmother, who transforms his button up shirt and black skinny chinos into a harness and jockstrap and sends him off the royal orgy. The next day Prince DomTop has to go around and top everyone in the village because it was a blackout orgy and he couldn't see anyone, meaning the only way he can find who Grindrella was is by remembering the feel of that bussy.