Monkey
,in sailor language, is the vessel which contains the full allowance of grog. Halliwell (Archaic Dictionary) has—
“Moncorn, ‘Beere corne, barley bygge, or moncorne.ʹ”—(1552.)
To suck the monkey. Sailors call the vessel which contains their full allowance of grog “a monkey.” Hence, to “suck the monkey” is surreptitiously to suck liquor from a cask through a straw. Again, when the milk has been taken from a cocoanut, and rum has been substituted, “sucking the monkey” means drinking this rum. Probably “monkey” in all such cases is a corruption of moncorn (ale or beer). (See Marryat’s Peter Simple.) (See Monkey Spoons.)