Dogging refers to people that enjoy the thrill of exhibitionism and sex in public spaces. Voyeurs are aware of favourite dogging spots and come along to watch the action. Consent is sometimes given for the voyeurs to join in the action.
Originating in the UK the term Dogging is thought to have been started as people walking dogs accidentally came across couples having sex in a car park or public spaces. Eventually it caught on and now there are thousands of fans all over the world.