cherries and blueberries
n.pl.— «“What is cherries and blueberries?” “it refers to the red and blue lights (cherries=red, blueberries=blue).”» —“Slang name you can’t stand?” by bdunndchi in Indiana Police Forums & Law Enforcement Forums @ Officer.com July 14, 2007. (source: Double-Tongued Dictionary)
Further reading
Joe from Fort Lauderdale, Florida, asks about pony, the term he and his fellow maritime academy students used to mean “a practice test” or “a copy of a previous test” to help them crib for an exam. Among 19th-century British students, the slang term...
You know the expression fly in the ointment: It’s that glaring typo on an impressive resume or that first scratch on a brand-new car—the one little flaw that spoils it all. This phrase goes all the way back to the biblical Book of Ecclesiastes! And...