The most acceptable forms of payment for the favor of being given a ride to any destination. Roughly translates to: money, weed, or sex (oral sex is also acceptable). Gifts should be given promptly and without hesitation.
Brian: Well, here we are.
Girl: Aw, well thanks for the ride Brian-
*she begins to exit the car*
Brian: Hey- hey, hey! Not so fast, its ass gas or grass in this car, bitch. And it seems I've got a full tank and plenty of the fine erb, so uhhh... *nods head, indicating genitals*
If someone is asking you for a ride and you don´t feel the need to give it away for nothing, it´s a good opportunity to ask for "ass, gas or grass".
Meaning you wish to take advantage of the situation by getting a good fuck, some bucks for the gas you´re gonna need or at least something to get a buzz from.
(Maybe one of you might describe it better, as I´m by no means a native speaker!)
"You wanna go to Mexico with me? Take a ride? Well, what´s your currency...
ass gas or grass ?
Nobody rides for free, you know?!"