This occurs when a male inserts a a thumb into the vaginal cavity (also known as the "lucy") while sticking the index and middle finger in her anus.
It resembles a male using the woman's ass as a bowling ball. It is known to be popular with horny redheaded women in the North Carolina area.
Damn, I bowled a strike wtih that chick from Raleigh. She loves getting the red-headed bowling ball.