Shrimp Backin'

The act of having noticeably poor posture, as a result of long-term slouching, causing a person's figure to resemble that of a shrimp.

Person #1: You trying to get into something tonight?
Person #2: My spine hurts from shrimp backin' all day.
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Person #1: Man, that dude over there obviously has scoliosis.
Person #2: That's ol' shrimp back, Jack, cut him some slack.