A fusty slut. Fustey being fucking busted (get it?). Her Muffin shop is always open, therefore being easily impregnated. Derivitive of the term "having a bun in the oven"
They usually have no standards.
That bitch is such an easy bake oven, she'll fuck anyone that shows interest.
The man was distraught to find out his wife is an easy bake oven, after the paternity tests.