"Showing some sack" is used to describe an action, behavior or display of ostentatious swagger -- an act that is perceived as extremely bold, audacious, or risky.
Similar to having "cajones."
Stephen Colbert was seriously showing some sack when he derided and embarrassed George W. Bush at the 2006 White House Correspondents Association Dinner.
It was quite possibly one of the finest moments in comedic history, I might add.
Attempting a fatal attack against an adversary. An attack intended to completely defeat and destroy one opponent, most particularly by attacking their vital weakness as if trying to sever the jugular vein.
The tactical opposite of "going for the capillaries."
In Star Wars, Luke Skywalker defeated the Death Star by going for the jugular and firing a proton torpedo volley into its main reactor, causing a chain reaction that destroyed the entire station.
Making an ineffectual attack against a relatively minor aspect of an argument or adversary, leaving the object of the attack unaffected.
An attack that is misplaced and off-target and does not address the fundamental issue.
The tactical opposite of "going for the jugular."
In argument, correcting your opponent's grammar instead of attacking her argument is an example of "going for the capillaries."
Eating so many berries that you get diarrhea.
Sam and I went berry picking this weekend, and we ate so many berries that we spent all of Sunday doing the huckleberry two-step, running to the toilet every 20 minutes with diarrhea.