An extremely reckless danger-wank whereby the performer has little or no hope of remaining undetected. Such a brazen act is brought about the liberation of knowing one is leaving and doesn't have to face the consequences of their actions.
Bazza: "Did you hear Dennis from accounts finally flipped the bird to his boss and resigned?"
Gazza: "Yeah, then Wayne caught him polishing his piece all over Cathy from finance's desk while she was at the post-budget sausage roll party".
Bazza: "An exit wank? Are you kidding me, what a way to go out!"