For the viewers of this exciting genre of porn it is often a total admiration of someone else's daring to step out of the social norm that gets them excited.
Exposing one's self in public is a form of exhibitionism.
A flash of tits, a sneaky flash of ass or pussy and even a blowjob or full-on sex outdoors - at parks, beaches, streets, restaurants and any number of public places can be extremely thrilling for the exhibitionist and equally so for us voyeurs.
Project Voyeur has been "documenting" incredible public nudity and sex acts in public and unusual locations since 1999.
There's something exhilarating about public nudity for both, the person who is nude in public (NIP) and for the people viewing the pictures and videos.