Chicken Charlie, it comes from a particularly dirty nasty ,tricky Job on old sailing ships," splicing the main brace " literally spliceing the main bracing rope from stem to stern of the ship to prevent the ship breaking its back in heavy seas and afterwards a tot of rum was given to those who had done the work.. as iron ships came in the term remained but ceased (like many things) to apply to the original task, and applied only to the post work free drink and then was broadened to mean any extra free, tot....and all you need now is the meaning of the terms "sippers" "gulpers" and "Viscious gulpers"