Sloot flute
An imaginary flute that, when played, signals the presence of one or more "sloots" (sluty women) in the vicinity. While playing the imaginary flute you may make the sound "Sloo-ta-loo" to let others know there are sloots in the area.
"dude, last night the sloot flutes were playing loud and proud!"
"Sloo-ta-loo!"
"Sloo-ta-loo!"