When two opposite gender siblings are having sex in the doggystyle posistion, the male pulls the sisters head as far around as possible and spits in her mouth while still inside her. Both sibling must be native Arkansas residents.
While on a camping trip in arkansas, three friends decided to pay 30 dollars a person to see a sibling fuck show. During the show one of the viewers asked if the man and woman could prove they were siblings. While fucking the woman from behind the man laughed and replied, "you just watch how I spit her mouth",(he yanks her head around and preceedes to spit into her mouth),"up round these parts we call that the Arkansas Switchback, and thats all the proof we need."
.......Actually a true Story!