When a non-gangster has a hard time keep their pants up, due to an unnaturally disproportionate butt that is smaller then the rest of their body. In effect, the person has to get tight pants, a belt, or walks around pulling up their pants up all day.
"Why don't you ever wear those pants."

"I can't, I have Gangsta Butt Syndrome."
by JesseCPK August 18, 2012
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