A fall. Formerly a bailiff caught in a barrack-yard in Ireland, was liable by custom to have three tosses in a blanket, and a squelch; the squelch was given by letting go the corners of the blanket, and suffering him to fall to the ground. Squelch-gutted; fat, having a prominent belly.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Squeeze Wax * SquibNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes