Most people know the acronym LOL (laughing out loud), but not so many know ROFL, it stands for rolling on the floor laughing or LOFL, which means laughing out fucking loud.
There are a lot more, like LMAO (laughing my ass off) or ROFLMAO, more subtle like LOTI (laughing on the inside), even really large and explicit ones, ROFLUISMP standing for (Rolling On Floor Laughing Until I Shit My Pants).
In fact, I think that you can mix them up to form new ones, like LOTIL or LOTIFL. Of course, you can invent new ones like FWMPL for fucking wetting my pants laughing or LUIWMP for laughing until i wet my pants.
So, having said that, the title ROFLING should mean ROFL-ing, i.e. rolling on the floor laughing -ing. The same as with coachball, i think this could be raised to sport, it's tiring and you use your muscles.
Among all of those acronyms I chose ROFL because LOL is so oftenly used that, for me, it isn't strong enough. I could have chosen LOFL, but the former make me smile and the later sounds to me like hypocrite.
Now, let me help you practice some sport, by posting a joke that made me ROFL (yes, you can use it as a noun!) for a while:
Three men, an Italian, a French and a Spanish went for a job interview in England. Before the interview, they were told that they must compose a sentence in English with three main words: "green", "pink" and "yellow".
- The Italian was first: "I wake up in the morning. I see the yellow sun. I see the green grass and I think to myself, I hope it will be a pink day";
- the French was next: "I wake up in the morning, I eat a yellow banana, a green pepper and in the evening I watch the pink panther on TV";
- last was the Spanish: I wake up in the morning, I hear the phone "green...green...", I pink up the phone and I say "Yellow?"...