As to where it came from:
the term dates back to the mid-19th century and the genteel world of British horse racing. Back then, a jockey who found himself way ahead as he approached the finish line would relax his grip on the reins and drop his hands. Not as confrontational as a spiked football, but still a bit of gestural in-your-face-ness. By the late 19th century, the idiom had been extended to non-racing contexts, and it remains in frequent use today.