your southern is showing 

A comment made to a person when they say something that reflects their upbringing in a Southern US State. Can be positive or negative.

Positive:

Regarding a person committing crimes :
Person 1: That guy needs killing.
Person 2: Your southern is showing.

Negative:
Regarding a person's ethnicity -- can be any negative word denoting skin color or culture or behavior:
Person 1: That "Nword" needs his ass kicked.
Person 2: Dude, rein it in, your southern is showing, and it is not cool!

your southern is showing by Atanastukate January 15, 2016