The woman grabbed McGraw in the crotch area at the close of his set Saturday as the 40-year-old country singer walked between the barricade and the stage to greet fans.
McGraw's wife, Faith Hill, who also performed on the Soul2Soul tour stop, berated the woman from the stage, calling her actions disrespectful.
"Someone needs to teach you some class, my friend," Hill said.
Clips of Hill, 39, singling out the woman were posted on various Web sites, including YouTube and TMZ.
"Within an hour, that video made it around the world," said C.J. Clement, who hosts a morning talk show on 99.9 FM KTDY with longtime partner, Debby Ray.
"Most said they were embarrassed this happened in Lafayette," he said. "They sided totally with Faith defending her man, standing her ground."