The act of a perosn who is chillin, or livin easy in luxury or style. Like a Cadillac Deville cruisen down Campleton road.
A: Ey, shawty, what good withchu killa!
B: Erething streiht nigga, im just lacin at the crib and blazin this phat ass philly.
A: Word nigga, ima come ova en a minute and lac which you homie.
B: Aight den, streiht up.
Lacin is the same thing as cadillacin. It's the shortened version and it means when someone gets drunk and high at the same time a.k.a. cadillacing
I had a shitty day but i dont care cause i know my jim beam and chronic will have me lacin later tonite.