The act taken by the passenger sitting shotgun described as putting ones naked feet up on the dashboard while driving around in a car, usually on a hot summer day, and often with one of the feet hanging out the window resting on the rearview mirror.
Craig: Oh gross! Check out the chick in the car next to us - she is totally dashboard surfing while her boyfriend is driving.
John: Yuk! Her toenails are skanky!
Craig: Oh my god, now she is sticking one of her feet out the window to rest it on the rearview mirror!