Balling or ballin' (in an older sense) comes from the term Goof Balls, which were amphetamines or uppers and were used as a recreational drug. (Also, as a method to avoid sleep by long haul truckers.) Hence, balling took on the meaning of being high or feeling "up". The term can be found in songs like "Thank You, John" by Willie-T and "Zydeco Ballin'" by Lil' Nathan.
I know that you been balling you're as high as you can be!
When balls usually belonging to obnoxious guys who think they're funny, usually named Caleb, end up in the face usually belonging to sluts, usually named Justine.
(After Caleb shoves his balls in Justine's face)
Justine: Caleb, stop balling me!
When something is so ballin' you have to give it proper grammer to show it the respect it deserves.
Indian-ass motherfucker: MY CAR IS BALLING
White Dude: like bling bling?
Indian-ass motherfucker: No you kids and your improper grammer, BALLING like BALL-ING.
White Dude: you dumb motherfucker indian-ass bitch.