You two may get good grades, but your last skit fell as flat as a pancake." What is the connotation of the phrase "fell as flat as a pancake" in this sentence?

Making a story about a myfwa(wolf and human) this is what i have is it good? my name is sylvia stone its been years since bunny's trusted us wolves and its stupid how this on bunny sellina bully's me only because i threatend to eat her years before we trusted each so mabey u might say she deserves revange is say i kill her once we start war harsh? ? if it is i dint give a single heck about it.plz tell me what to fix and u can edit it if u would like the pic is what i want her to look like i didn't want to show her face yet.