The story
From bisexual (adjective) + lighting (noun), referring to the pink, purple, and blue colours of the bisexual flag (also known as the bisexual pride flag).
Etymology from Wiktionary, CC BY-SA 4.0.
bisexual lighting
bi·sex·u·al light·ingToday it means: The simultaneous use of pink, purple, and blue lighting, often to indicate bisexuality. Full definition →