Laugh my fucking dick off.
Used in really any case where your friend or enemy or pet turtle texts you something funny.
Should not be used in cases where the person will blackmail you for laughing at what they said. Shown in example #2.
1)While texting:
Person 1: "Damn she looks mad ratchet"
Person 2: "Lmfdo! Dude you're hilarious, that's so true though..."
2)
Person 1: "She looks like she gained some weight, poor girl. I heard she caught herpes too, shortly after her mother was killed in that car accident yesterday."
Person 2: "Lmfdo! Sucks to suck."
Person 1: "You're an asshole! We're no longer friends! I'm telling the whole school about how you're an ass-licking mother fucking gay rhino-raping fat piece of vanilla flavored shit in a dumpster full of fat rats drinking kool-aid riding unicycles while singing random justin bieber songs.... No nipple having bitch!!!"
Laughing My Fucking Dick ofF.
Used by internet intellectuals.
A good alternative for the medieval 'LOL' and ancient "LMAO'.
Used by people of the modern age.
Bob: "Dude I was fucking your girlfriend and out of nowhere she farted like an elephant who accidentally ate a jumbo cheeseburger!!"
You: "LMFDF!"