To relax comfortably i.e. "I was lunched up" or Nah man, im just lunching"
Also used to describe
failure "Did john pay you that Fiver?"
"Nah man, he lunched it"
Also can be used to describe someone (usually a cainer) who fails at a lot of things. "Did you get that job?"
"Nah man, I lunched it"
Or
maybe in sport.....
Ha man you lunched that last
shot!"