Put your money where your mouth is. Fish or cut bait. S--- or get off the pot.
Fund and man this project to proper levels or let me out of this loozer contract.
This idiom is a response to non-committal behavior and is not the same as ShapeUpOrShipOut.
Also used as a response to arguments repeatedly advanced without evidence or justification, as a call either for that evidence or the retraction of the argument...see ThatIsJustTheWayWeDoThings.