put on the red light

put on the red light

slang To make it known that one engages in prostitution. Refers to the use of red lamps to show that an establishment is a brothel. A: "Tom's new girlfriend used to put on the red light—if you know what I mean." B: "Whoa! Does he know that?"
See also: light, on, put, red
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.