steal-me flag
n.— «It’s called the “steal-me flag.” Before the little red flag on your curbside mailbox alerts postal carriers of outgoing mail, it sends a clear message to thieves.» —“How you can help stop ‘check washers’” by Rhonda Sciarra Chicago Daily Herald (Illinois) Aug. 12, 2002. (source: Double-Tongued Dictionary)
Further reading
After our chat about tongue twisters, a Chicago, Illinois, listener shares one that looks much easier than it sounds: Irish wristwatch. This is part of a complete episode.
Related
Michael from Jones, Michigan, says he was stationed on a U.S. Army base in Germany in the early 1960s. If there was a gust of cold wind, a fellow soldier would say the hawk’s out. This expression is largely associated with Chicago, Illinois...