You can expend a luck reroll to reroll a stabilization check. In addition, once per day, whenever you have at least 1 hit point remaining and would be dealt enough damage to kill you, you can expend one luck reroll as an immediate action to take only enough damage to reduce you to -9 hit points. You automatically stabilize. You gain one luck reroll per day.
Unlike most other luck feats, using Tempting Fate requires no action.