The act of putting one's hands upon wood grain, an often faux-wood type of molding often found in luxury automobiles, especially on the steering wheel. However, in some cases, the wood is actually real. Gripping grain is often paired with leaning to one's right while driving.
If you're driving down Peachtree Road on a saturday night, you better be gripping grain.
Holding onto a wood grain steering wheel
I drove past tipping gripping grain.
"You peeping him take a picture, that chrome and that paint official
You smoking then take a swisha, there's plenty just take 'em wit ya
You chilling you ain't a sipper, then I'ma be hanging wit ya
Take a hold of the grain and grip a, handful and smile for the pictures nigga"
Chamillionaire - Picture perfect