Laughing My God Damn Ass Off. Based off of LMAO which means Laughing My Ass Off. Can also be used after ROTF to make ROTFLMGDAO (Rolling On The Floor Laughing My God Damn Ass Off.)
D00d 1: Yo, my homie Joe got his dick in a cast because he fell off the roof working on our dish!
D00d 2: LMGDAO!!!