Police are investigating an "unexplained" death at an event which describes itself as bringing "kink to the foreground of festival culture".
The man was pronounced dead on Tuesday morning following the Flamefest festival which took place in Tunbridge Wells, Kent, over the weekend.
An unconscious woman also received medical treatment and was taken to a local hospital by air ambulance, Kent Police said.
It was the second year that Flamefest, which boasts a "discreet" adult play area and an outdoor dungeon, has been held.
The event, which was "furnished with fetish play equipment" where campers can "explore pain, experience pleasure and fulfil your fantasies", took place from Friday to Sunday.
Organiser Helen Smedley created the festival "to bring together the purest, most hedonistic elements of the party scene", according to its website.
Ms Smedley declined to comment on the unexplained death.
A police spokesman said: "Kent Police is making inquiries to establish the circumstances surrounding an unexplained death in Tunbridge Wells.
"Officers were called by South East Coast Ambulance Service at 6.14am on Tuesday 22 August 2017 to a medical incident at a campsite in Powder Mill Lane, Tunbridge Wells.
"Patrols and ambulance crews went to the scene where a man was pronounced dead. The death is being treated as unexplained at this stage.
"In addition, an unconscious woman received medical treatment and was taken to a local hospital by air ambulance."