Some one who doesn't know how to pull up their saggy pants (mainly chicks)
That sacker Crack needs to pull up her pants!
Someone who hits someone else in the ballsack.
Person 1: "Dude, Trey just hit me in the balls!"
Person 2: "Wow, I didn't know that he was a Sacker."
A man who tucks they’re nuts and you can see them from the back.
Your a Back Sacker because I can see your nuts from the back