Brewer's: Grease One's Fist
or Palm (To). To give a bribe.
“Grease my fist with a tester or two, and ye shall find it in your pennyworths.” —
S. You must oyl it first. C. I understand you - Greaze him i' the fist.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894