Abbreviated form of "Laugh Till My Pants Fall Down". Similar to "Lol", "Lmfao" and "Rofl". When used people generally think that you are laughing very hard,, so use with caution. When said out loud , sounds retarded. Also,, leads to some perverts asking for a photo of you with your pants down...(true story). :]
Boi: *Insert very lame joke here*
Gurl: Hehe, LTMPFD !! That is lyk, soo funni :]]
Boi: Erm, realli? i didnt think it was that funni...:O
Gurl: I know, i was been sarcastic :O
Boi: Oh, okay, well since yawr pants are down can i get a pic mebe?;)
...Gurl is now offline...