Something you say when you're heading towards the inevitable. Usually either impending pain or doom awaits you. Intended to be humorous, or as a reminder that others have suffered worse and you now join their ranks.
The Green Mile was a short walk prisoners had to walk before facing execution. To say "Walking
the Green Mile" was a way to tell other prisoners that
you wouldn't be coming back from where the guards were taking you.
"Walking
the Green Mile, better get right with Jesus."
Little Tommy said "Walking
the Green Mile." when they called him to the principal's office.
Goobs said "Walking
the Green Mile." as he approached the restroom after a 5 day pizza binge.