A person, usually male, who shows through some daring deed or antagonistic word-play, that they are truly weighed down by the size of their metaphorical testicles.
Daring, to the point of being foolhardy, confrontational or overtly aggressive.
An excessive amount of confidence.
""Dude, you put a live wolverine in your pop's Liquor cabinet the morning of the Super Bowl? You got some wicked sack!"
(you knock over a 350 pound biker's harley and spit in his face) "Boy, you got some Wicked Sack!!!"