Being rich as fuck, ballin' outta control. Racks is a synonym for stacks; a stack being $1,000. Basically, if you stackin' money crazy high, you got racks on racks on racks. Made famous by Yung Chris' hit song 'Racks'.
That nigga Yung Chris might not have had racks on racks on racks before that song, but that shit is a hit, I bet he's rollin' now.
Originates from casino the gambling term "STACKS ON RACKS." Plastic "racks" hold "stacks" of 100 casino chips each. Since casino chips are uniform in size, a rack can hold $100 (if $1 chips) up to $500,000 (if $5,000.00 Chips). The "racks" themselves are also stackable. So RACKS ON RACKS describes the stacking of plastic chip racks....each holding stacks of up to 100 casino chips of any denomination as described. AKA a shitload of money.