Advance Wars – What the hell does “Possum spit”

mean? Grit says it on mission 2.
Answer #1
It’s the Nintendo sanitised way of saying “bloody hell it’s ..”
Or “holy shiit” or..
Answer #2
How’d you know?
Answer #3
Actually, I’m only part right: It depends on the context.
“Possum spit! I’m not doing that!” or “I ain’t doing possum spit!” = “Bloody hell, I’m not doing that!”
but
“You ain’t worth possum spit” = You are worthless.
It either refers to something worthless, valueless or it’s an exclamation of disgust or denial.
“Like possum spit I’ll so that”
“That picture is worth possum spit to me”
“Holy possum spit, Batman, the Joker’s got my balls in the vice!”