To pump. To draw from a man all be knows. The file sucked the noodle’s brains: the deep one drew out of the fool all he knew.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Suck * Sucking ChickenNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes