it means Rolling On The Floor Laughing My Ass Off.
its usualy said when someone says something extremely funny. it comes from "Rotfl" (Rolling on the floor laughing) and "lmao" (laughing my ass off". it is often used in the same case as "lol" (laugh out loud).
molly: today i was walking down the road in the ice, i slippedon the ice and fell on my back.
tilly: lmao
molly: what? it's not funny, I could have really hurt my self!
tilly: rotflmao
By Karine
Rotflmao
Rotflmao is a word used by those who repeatedly hear the acronym " LOL " and find it extremely monotonous.
Rotflmao was created by 3 fat men at a pub in bournemouth, England upon watching their dear fat friend jim rolling on the floor laughing his ass off at a joke made by fat friend jeff.