An abbreviation for Diarrhea BlowOut. A DBO is a special type of shit. It isn't any normal case of the runs, but rather the type that makes your sphincter ache for days. Some traits of a DBO are loud anal vibrations, hot burning sensations, and a powerful jet stream often accompanied by splashing.
(Person 1 returns to the lunch table and begins talking)
Person 1: Dude i just had the biggest DBO of my life. Waffle house must make their waffles with shitty ingredients.
Person 2: .........