‘Blow a raspberry’
“Blowing a raspberry” is when you place your tongue between your lips and blow to produce a rude sound similar to flatulence, usually to signal your derision toward something.
Used in most English-speaking countries since at least the late 19th century, the phrase is an excellent example of Cockney rhyming slang, a humorous type of slang associated with the English working class and used throughout Britain.
“Raspberry” is a shortened way of saying “raspberry tart,” which rhymes with “fart”; ergo, “raspberry” is slang for “fart.”
