In short, a longer phrase that can be used when something is cool, and awesome, but doesn't mean its extremely cool. Instead of saying coolio, or cool all the time you can say this word.
Also can be used if Person A says something, hoping that Person B will say that it was cool, but person B can just say "coolioliosis" and Person B doesn't really have to agree that its cool. Like if he is doing something else, he can just say "coolioliosis."
Person A: Dude i just made out with some hot chick!
Person B: Coolioliosis.
Person A: Dude that movie we saw was awesome!
Person B: I know it was coolioliosis!