Friendship Incest Syndrome is an occurrence where you have a group of friends who have all dated and broken up with the same people, then you are eventually forced to be friends with an ex because they're still in your circle of friends - in fact they're probably dating one of your friends by now. It effects a small # of people, likely living in Southern California. It extends to Frenemies who have removed themselves from the circle whom you can never fully get away from.
I'm going to a concert tonight, oh jeez, Robin & Joe are going to be there...Friendship Incest Syndrome (FIS).
by Ms. Woods July 7, 2010
Get the Friendship Incest Syndrome (FIS)mug. 
Get the incest is the best put your sister to the testmug. Brent Austin Miller (terrorist) from Lytton, Iowa fucked tiffany johnson also from Lytton Iowa when she was 13 and he was 18 and then again when he was 19 and then he took his sister to her senior prom and tried to get laid........he succeeded he also has a gay ass jewfro and a small dick that didnt please tiffany or his sister.
by chandlerjepsen11 September 30, 2012
Get the brent is a pedophile and incest loving jewish bitchmug. the feeling you get when two of your friends suddenly get close and act like a couple when they insist they’re just good friends. Instead of being cute, though, it just makes everyone feel creeped out. It’s like watching a brother and sister flirt....
“Have you seen the way Rachel and Nick have been acting lately?”
“Yeah man, it’s giving me incest vibes”
“Yeah man, it’s giving me incest vibes”
by Sheeepherder December 19, 2017
Get the incest vibesmug. 
The act of shipping or the existence of a couple that have a sibling relation ship or are adopted siblings
''omg did you read that JayDick fanfiction?''
''No dude! They're like brothers that's spiritual incest!''
''No dude! They're like brothers that's spiritual incest!''
by Insert Dorky Nae May 9, 2017
Get the Spiritual incestmug. when a friend has started dating his friend ex whilst staying in the friend group as everyone involved, this also includes people in the group that like other people in the same group but are friends with the other ex. Breaking the bro code simultaneously.
steve goes out for Lara for about a month but it didn't work out, after a few weeks Lara goes out with bob, committing group incest but not severely. However, as they were dating steve was simping for Lara clearly prioritising plans with her above everyone else clearly committing group incest. All in all this situation wouldn't happen if the group would not commit group incest.
by @annonymous123 December 27, 2020
Get the Group incestmug.