look up any word, like muddin:
 
1.
When 2 family members have sex with a step family member.

eg: Father and Son have sex with new Wife/ Step Mother.
Steve: Did you hear about Daz?
Pete: No
Steve: Him and his Dad did the hillbilly!
Pete: They Hillbilly'd his Stepmum?
Steve: Yep!!!!!!
Pete: Well she is hot......
by vox plasmator August 16, 2010