Friendship Incest Syndrome (FIS) 

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).

Friendship Incest Syndrome (FIS) by Ms. Woods July 7, 2010

economic incest 

Screwing a family member on a business transaction.

He paid his sister so much below market value for that property that it was economic incest.

economic incest by ThorMonster March 29, 2016

Chinese Incest Trap 

When you are stuck 1 inch in your mom and your dad is 1 inch in you. You aren't able to exit to the sides, either you go deeper in your mom or go back and let your dad get deeper in you.

Mike: Hey are you ok, you look pretty shooken up pal.
John: No I'm not alright. I got stuck in a Chinese Incest Trap last night.

Chinese Incest Trap by Moist Sperg July 8, 2020

Gay Incest 

The act of having a same-sex sexual relationship with a close blood relative.

Could bro-bro, sis-sis, male cousin-male cousin (only if they're first cousins) and etc.

Bob: I just had sex with my newphew.

Joe: Your into gay incest!!!

Gay Incest by Rackinghedgeman July 26, 2011

Woody Allen Incest 

The creepy act of getting into a relationship with a "step" or distant member of your family, such as a stepchild, second cousin, or "stepcousin". This type of behavior is not illegal, but definitely creepy. Named after Woody Allen, who married his ex girlfriend's adopted child. (Arguably if not definitely his stepchild.)

Mark: Hey I wanna hook up with Sarah, she's my uncle's stepchild, but that doesn't make us biologically family!
Joe: That's Woody Allen Incest! And fucking disgusting. Even though I'd plow her hard.

Woody Allen Incest by NemoHavok June 18, 2009

academic incest 

When a college or university hires its own graduates back as professors, especially when they have little to no professional experience in their field.

The academic incest in RISD’s architecture department has led to a decay in faculty quality.

academic incest by Goblinoid February 20, 2020

roommate incest 

engaging in "bedroom" activities with ones room/housemates.

my roommate invited me to hook up with her and her fuck-buddy! like a threesome!... i do NOT participate in roommate incest thankyouverymuch!!

roommate incest by veronica corningstone April 14, 2006