Usually used in response to something that has made you laugh so severely that you have lost the will to live. Not to be confused with dying ded dead im dead or deceased this is much worse. You have an absolute zero percent chance of resuscitation. You've been morgued
Eli : yo I'm grabbing a coffee on my way over, you feelin' it?
Stewie : bet
Eli : baristas aways lookin' like they have a degree in lesbian dance theory.
Stewie : 100% morgued