family tree climber 

One who dates someone with a large immediate family so that they can eventually get with every other member of the family. They usually originate from the south but have come as far north as Mississippi and Oklahoma. They engage in redneck activities and often enjoy incestual activities.

Joe: "Have you seen BillyBob, he's such a family tree climber..."

Duane: "I heard he only dated Janessica so that he could fuck her sisters and eat out her grandpa."

family tree climber by el chunkster January 2, 2017