Laughing My Fucking Ass Off. A term used when you are in tears from laughter. Used mostly on instant messaging.
Ben: I did the stupidest thing last nite, i was running down the street with Alex and I ran straight into a pole, i ran so hard i think i dinted it!
Kyle: U are such an idiot. l.m.f.a.o!
Kyle: U are such an idiot. l.m.f.a.o!
by Jessie_xxx November 20, 2005
by Diego Delgadillo November 11, 2006