ROTFLSTC 

Rolling on the floor laughing, scaring the cat.

Jim: Omg did I tell you that funny joke about the beaver??
Bob: Haha yeah I was ROTFLSTC!

ROTFLSTC by Shigglee March 1, 2009

ROTFLBTCDICAJTTWADBSIHPWTRHITSBKABAYB 

That's the longest Internet-acronym i've ever heard. It does mean:

Rolling on the floor laughing biting the carpet dancing in circles and jumping through the window almost dieing by smashing into HP who's then running horrified into the street beeing killed accidentally by a yellow bulldozer.

A: woo! i'm the haxxor!
B: ROTFLBTCDICAJTTWADBSIHPWTRHITSBKABAYB

ROTFLBTCDICAJTTWADBSIHPWTRHITSBKABAYB by Visor December 8, 2003

roflstc

"rolling on floor laughing, scaring the cat"
a suffix to the good ol' Rofl

A:'rofl!'
B:'roflstc!'

roflstc by Gees6335 September 10, 2006

roflstciiho 

'rolling on (the) floor laughing, scaring the cat if i had one'
used as a suffix to the suffix rofl - with the note that you don't have a cat

A:'rofl!'
B:'roflstc!'
A/C:'roflstciiho!'

roflstciiho by Gees6335 September 10, 2006