1. A huge, gaping maw of a vagina with not only inner and outer labia, but several folds of skin in between said labial regions, resembling a cabbage; quite possibly smells like old rancid cabbage as well.
2. Non-sensical term coined by South Park's episode called "It's a Jersey thing". Mostly uttered in anger.
Angry hair dresser: That whore is gah-bage! That muff cabbage thinks she's hot shit, but she's just nothing, she's just a cabbage!!
Innocent bystander: What the fuck is muff cabbage?!
A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"