To let loose one's bowels in a prostrate position. Usually within the presence of an audience during times of pleading or begging for one's life.

(The term "sluko," was derived from an unexpected situation during which a prisoner, after discovering his sentence, had dropped to the floor begging.

It was at this point the prisoner, who had been extraordinarily gassy from a poorly made meal, accidentally let out a very wet and eruptive load which spilled out the top of his britches.

Looking at the slimy mess that had been oozing down the prisoner's back, the judge replied with surprise, "SLUKO!"
An unexpected conversion of three phrases, "Uh oh," "Yuck," and "Slimy!")