say someone has a double chin but they are skinny....that means they have a "wolf's neck". Wolves have an extra layer of skin on their neck to protect their arteries and stuff. So, instead of saying u have a double chin when you are skinny...say u just have a wolf's neck.
Man:"How come you have a double chin even though you are really skinny?"
Woman: "It's not really a double chin, it's more like a wolf's neck."