A fork of Rural Dictionary
the initials for "in my space boots". when talking on an instant messanger, the use of "rofl" and "lmao" is common.You simply add "imsb" onto the end. Thus creating "roflmaoimsb". "rolling on floor laughing my *** off in my space boots". Makes chatting online more enjoyable.
"....omg that's so funny!" "roflmaoimsb"