An extraordinary mode of imposition, sometimes practised in the country by strolling women, who have the knack of counterfeiting extreme pain, pretending to have a small animal called a wolf in their breasts, which is continually gnawing them.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
To Wobble * Wolf In the StomachNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes