when you run out of funny shit to say when something happens, so you just say this
mark: dude, stacey just fucked your cousin!
chad: are you TITTING me?!?
mark: heh never heard that before lol nice
this means "i still want to die, tho" so you should probably stop looking at this and attend to your friend
gregg: are you feeling any better?
dan: ye, i guess. iswtdt
gregg: oh..