This subculture involves arousal from the idea of a full bladder or public "urinary desperation".
The phrasing ("seduced," "public toilet," "exclusive") most likely refers to a specific title from the Japanese adult video (JAV) industry, where such high-concept scenarios are common. Cultural Study of Public Spaces: japanese love story is seduced in public toilet exclusive
Examples of the public's reaction include: This subculture involves arousal from the idea of