AND GET COCK ROACHES. A sea term for masturbation; a crime, it is said, much practised by the reverend fathers of that society.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
to box the compass * braceNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes