Friendcest occurs when one person dates a bunch of people from the same group of friends, usually one at a time. This is often partially the fault of the group of friends, as they do not learn from their friends' mistakes.
Kenith had dated Camille, tried to date Brittany, and now is going after Brittany's sister? Woah thats major friendcest.
When someone screws up and their parents find out and get angry and prohibit them from doing stuff. A teenager form of grounding.
Marco couldn't come play and canoodle today because he's on punishment.