This is a pretty crazy picture for those that want to play detective. If you try to look at some of the smaller details, it is going to be obvious that the girl probably had sex on top of the car the night before. To be precise, either he did have sex, or someone close to her. The tell-tale sign are the hand marks on the car's hood.
There is no other logical explanation why the car would have two, side by side, hand marks on its hood. Even if someone was drinking close to the car, they wouldn't be holding their hands like that. Another interesting detail is that there is a line that goes from one hand to other, almost as like someone was sitting on the hood, while someone else kept both hands in the front.