I love that she's looking up to watch the action, not just lying back passively.
And her nips! Are they hard from the cool mountain breeze, or the wind from all the traffic rushing by their roadside rendezvous?
Remember when the only sex we had was in the back seat of a car? Now, no one waits for nightfall, and the front seat is just as popular. And if there's an audience outside the windows - so much the better!
Back in the day, we would find a secluded spot to park at night, for some back-seat adventures.