It is when after your daddy has finished inside your sister, you dump a lincoln log inside her snooch, while your mama waits for the contents to pour out on the graham crackers to enjoy. May need to adjust roles based on which family members are available.
Jerry -- Your mom's asking for another Louisiana Campfire.
Nicole -- Again?!
Jerry -- God dammit Nicole, quit your bitching. ZACH! GET IT IN HERE AND HELP FEED YOUR FAMILY!