The area between your legs and your arse. Presumably meeting the barse at some point, becoming the blarse.
Here is my larse
The tendency to write like a goddamn fucking idiot by writing half in capital letters and half in lowercase letters. A sign of douchefaggery.
"Tony is larsing again."
"What'd he type this time?"
"HEy. wE SHOulLD haNG oUT TOdaY."
"Ouch. That *is* a larse."