roflmstd
Roll on floor laughing myself to death. Meaning your laughing so hard you're weezing. Or something like that.
Person 1: I am so epic, I jumped off a roof, went through a window, missed my horse, broke my neck, died, and then came back. All because my mom said two things. "Don't stand on the roof" and "Hold onto your horses."
Person 2: Roflmstd!!! You fail!!
Person 2: Roflmstd!!! You fail!!