Car Pool because car pool means you are giving people rides, you are usually giving multiple persons rides. Giving someone a ride taken as a sexual innuendo means having sex.
car is full = perfect ratio of women to men
Dude 1: Hey man want to go to the club tonight?
Dude 2: Nah man I don't want to waste my time with a bunch of sligs. Besides I'm car pooling tonight.
Dude 1: Oh can I come?
Dude 2: Sorry man the car is full.
Playa: Do you need a ride?
Slig]: Yeah is it kool if we car pool? Some of my friends want to come with.