Verb. Etymology: coming from the modern car tuning scene.
a phrase that means to modify a vehicle with as many types of aftermarket parts, performance or visual-wise, as are supported by that certain vehicle.

to adorn or decorate in an extravagant or gaudy manner

To trick out is to put your girlfriend out on the streets, turning tricks. Frequent tactic of low-life sludge who get nice girls hooked on crack. Once they're hooked tricking them out is the next step. The sludge then has dual trade.

(v) (to trick out)

When you're makin' mad-sweet love to a lady friend and someone reaches behind you and tickles your balls, that's trickin' out.