A kind of short jogg trot, such as is used by women going to market, with butter and eggs.—She looks as if butter would not melt in her mouth, yet I warrant you cheese would not choak her; a saying of a demure looking woman, of suspected character. Don’t make butter dear; a gird at the patient angler.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Buttered Bun * ButtockNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes