Two randy gals get picked up by a driver in a car and get excited when they watch him stop for a pee. So they bounce out of the car, hike their skirts up, and pee also. Soon they are naked, fucking and sucking in the grass, then it's back into the car and down the road again. This vintage circa 1915 stag film, A Free Ride, is said to be the first American-made stag film. See wikipedia for more details.