The arch in a girls back when she pushes out her ass and tits at the same time in an attempt to look sexy or slutty. The resulting arch is a slutback. Some arches are natural, others may be forced.
A slackback is referring to a day when you are slacking off from dialing and selling. It can also mean a day that you did not post any new sales on Slack.
Becky "I just got a chargeback."
Mandy "Girl, I hear you, but you have seen your slackbacks? Get rid of those days and the chargeback will disappear."
Etymology: from the practice of running from Europe and crossing the Atlantic Ocean to The Americas
Date: 2009
usually offensive : a European who enters Anahuac
Similar to "Fives" or calling "shotgun", "Quack Quack Seatback" is a common way to lay short-term claim to a seat you're about to vacate when with a larger group. Sometimes shortened to "Quacks."
Person A: "Hey, you stole my seat."
Person B: "It's my seat now."
Person C: "No, he called Quack Quack Seatback. Move it."