lmaomfg 

lmao means "laugh(ing) my Fuckin (or freakin) ass off"

omfg means "oh my fuckin(or freakin) god(or gosh)"

lmaomfg is a combination of the two, but it only has one "o" to save time.

ppl #1: hey look at this hilarious pic!

ppl #2: lmaomfg!!!!!

lmaomfg by a persin April 10, 2008

lmaomg 

LaFF My Ass Off-oH My GoD

Today I got high and thought of a new slang "lmaomg" during when I was laughing hard for no reason. Therefor I decided to be the first person to define it on urbandictionary.com.
However, I found in fact I was already the 14th wannabe...
Then I started laughing hard for a reason...

lmaomg by htp-rck February 11, 2008

LMAOMG 

combination of laughing my ass off (LMAO) and oh my god (OMG). it's used when you find something funny and while you are laughing you realize the true commedy behind it and decide its even funnier than in the first place. Slightly more funny than LOMG and a lot funnier than LOL.

LMAOMG that was sooo funny.

LMAOMG by smoen81 January 22, 2006