Try this to torment your road trip companion who is hoping for pussy in exchange for doing all the driving. Make sure he drives. The make of car is irrelevant. Bring a vibrator with you and as you're heading down the highway lift up your skirt so he has a great view of your best parts and use the vibrator on yourself and make him squirm as he listens to you cum and cum and cum as the miles roll by. You'll feel good, less bored with the trip and the torment will be complete when you reach your destination and tell him, sorry but you're all cummed out and need to sleep.