Thanks Teacher Lori. I was confused because I heard a bunch of flowers , a bunch of teen-age boys. Shouldn't it be a bunch of evils? Shoved up means combined here? The butt of an evil mannequin seems to mean just one buttock :) Somehow the words being combined together have confused me as I am not a native English speaker.

Evil is an uncountable noun in this case. It is plural when you say a sentence like: All the evils in the world make me feel hopeless. A mannequin is a plastic copy of a human in a store for displaying clothes… so the sentence means a person is doubly evil… someone is so evil it’s like they are a ball of evil living inside the rectum of an evil plastic, unfeeling fake human.