The exhibitionist saw a sunbathing girl in the field and offered her to masturbate on her. The girl did not refuse and even jerked off to a stranger herself. As a result, the exhibitionist cum on the girl's body
The fly buzzing around his dick was funny. Panning the camera to show that there was no one in sight served no purpose. Obviously, Amy’s boyfriend was playing the part of the exhibitionist. A real exhibitionist would have cum much sooner. Interesting fantasy though.