couch rocket
n.— «You can refer to the 650 as a couch rocket, but don’t tell your wife.» —“Hello from Georgia” by allwalk in Toronto, Can. BurgmanUSA.com May 1, 2004. (source: Double-Tongued Dictionary)
Further reading
Megan from Savannah, Georgia, is curious about a phrase her father used: down cellar behind the axe, a phrase whose meaning she never quite understood. Down cellar, meaning “down in the cellar,” is common in New England and the Canadian Maritimes...
A Navy veteran recalls hearing the Southern expression fat lighter from his wife’s family in Troy, Alabama. It denotes an old, resin-rich pine wood that becomes highly flammable as it ages. Fat lighter is prized as kindling and often called fat...