Right, so back to the balls. It’s clear they represent the intersection of two universal and timeless human fascinations: money and genitals. But when did touching them become good luck? Why do Brazilian businessmen rub their briefcases against the giant genitalia? Why do groups gather around the bull’s majestic butt crack for family photos, parents gently pushing their children to climb underneath and hug the balls from below?

Source: Tourists Love to Rub the Bronze Balls of Wall Street’s Charging Bull Statue. Why? | Atlas Obscura