An insult applied to a dim-witted, brainless person.

when you're hungover as shit after a spending a night drunk as a skunk

A dumbo who has poo for brains and therefore thinks stinky thoughts.

A poobrain pu-brane is a cranial sheister.
A turdiliacus of the highest order.
Usually recognized by an indiscrete smell of faeces.

After a women has consensual fun eating out the rim of the anus after a stinky she then proceeds to give you that goose neck resulting in poo residue on the penis