look up any word, like the eiffel tower:
 
1.
Can either mean laughing my fucking cum out, laughing my fucking cock off or for girls laughing my cunt off.
Person1 did you see ____s pants fall down yesterday?
Person2 ya I was LMFCO
by Urban dict. User December 11, 2009
 
2.
Laughing my fucking cock off. A term used in response to something funny.
I was lmfco when the cop on South Park shat jizz after being gangbanged at a frat party!
by GoofBall January 11, 2013