Green’s Dictionary of Slang

to toady to, to curry favour; thus pot-licking n. and adj.

[1865		Wkly Perrysburg Jrnl 1 Dec. 1.5: You cowardly, sneaking, plate-licking blaggard].
1929		W. Faulkner Sartoris IV. 282: Hole up here, you potlickin’ fool. They whimpered and surged.
1968		‘Sl. of Watts’ in Current Sl. III:2 38: Pot-licking, n. Oversolicitous behaviour.
1968–70		Current Sl. III–IV (Cumulative Issue) 95: Pot-licking, n. Oversolicitous behavior [...] He made his way to the top only by pot-licking.