The short plea Our Lady asked to be added after each decade of the Rosary.
One sentence, asked for by Our Lady at Fatima in 1917, prayed after the Glory Be at the end of each decade.
When: Within the Rosary, and on its own as a quick act of mercy for others.
Why: It widens the Rosary outward. You stop praying only for yourself and start asking for those with no one praying for them at all.
O my Jesus, forgive us our sins, save us from the fires of hell, and lead all souls to heaven, especially those in most need of thy mercy. Amen.