Yeah. First time was in my car at the drive in with my (at the time) girlfriend
Okay so only recently did I get to experience the whole 'loving in the back seat of a car' thing, and I gotta say it's a forgetin' TERRIBLE experience.
There is not enough room. Period. Maybe if you drive a suburban or a hummer or something, but in the back seat of a family sedan there's just not enough room. The available angle of entry is smaller than you might think, so to get a comfortable position for both you and her (I assume this would be even more difficult for gay dudes) that offers an available angle of entry is like human Tetris.