I’ve seen it on the Sopranos, and I’ve seen it when I was growing up in a city with a large Italian-American population.
What is it? The Italian-American version of finger pointing. Instead of using only your index finger, Italian-Americans often point with their index finger and pinky, with their thumb in the air. It’s like the “rock on!” handsign, only pointed horizontally instead of vertically.
Why do Italian-Americans often point this way? Do they consider one-figner pointing to be offensive?