when you get entirely wasted to the point you barf and fart epic amounts at the same time.
sometimes results in a friend having to check the barfarter's pants to make sure it was only a fart.
Jane- "Hi Lou. How was your weekend?"
Lou- "Fine. How was yours?"
Jane- "Pretty swell. Except Sally got so drunk at our party that she barfarted everywhere."
When you're so down bad that you need an extension of the phrase to define just exactly how down bad you are. This version of down bad doesn't always have to be applied sexually. It could mean you're down bad for a delightful date, or you're just doing shitty in life overall.
In other words, you're either doomed or desperate as hell.
Chad: "Bro, my girlfriend broke up with me AND I failed finals."
Brad: "Man. You down badarious, dude."