A particularly hard rain storm. In other words, it's coming down so hard, it's as if a cow is pissing on a flat rock.
"Wow, look at them clouds rolling in."
"Yep, it's getting set to rain like a cow pissing on a flat rock!"
"Yep, it's getting set to rain like a cow pissing on a flat rock!"
by HAL 9000 February 26, 2008
Get the Cow pissing on a flat rockmug. "Sheeeeeet! It sure is cumin' down out there! Raining like a double-cunted cow pissing on a flat rock!"
by Carl J. Maltese April 28, 2007
Get the raining like a double-cunted cow pissing on a flat rockmug.