A person who consciously aims to have sex with celebrities and then brags about it to their friends or the press to bolster or boost their ego or social status. It's also a word that will pass through any e-mail marshall a corporate business may have.
Siblings that fuck each other. Brothers on Sisters, Sisters on Sisters, Brothers on Brothers, Brothers on Brothers while their Uncle watches from the closet.
Setting: Father of 2 daughters at bar with a friend.
Father: “I walked in to my oldest daughters room Late last night to borrow her iPad & witnessed both of my daughters in bed in the ‘69’ position. WTF???
Friend: “Sounds like you’ve got a case of ‘Sibling Fucklery’