1. A process to flush the all the current thoughts, views, headaches, and/or attitudes of an individual. Usually involving drugs, a blunt force to the head, electroshock therapy, meditation, frontal lobotomy or other brain altering procedure.
2. A strong alcoholic drink, or combination of alcoholic beverages to induce forgetting about the current situation or problem.
"This headache is killing me, I need a brain emena!"
"I know just what you need to get your ex out of your head. We will go out on town and give you a brain enema!"
when a person constantly talks shit and is in need of a good flushing of their thoughts and concepts.
it appears bill needs another brain enema hes over there talking up a good batch of shit again.