Empty Nest Syndrome. Occurs when a child is about to leave home for the first time and parent begins to realize what it will be like to not have kids around.
Mom: My babies are all growing up!!! :'(
Kid: You're showing signs of ENS
Erect Nipple Syndrome. Caused by arousal/low temperatures.
"In the freezing cold changing room, it was easy to see she had ENS"