I love these little prayers and I pray them whenever I can:
“Sacred Heart of Jesus, once in agony, have pity on the dying.”
“Immaculate Heart of Mary, pray for us, now and at the hour of our death.”
I am very dedicated to the Sacred Heart, and I love this prayer that I learned from my former community of interest, the Carmelite Sisters of the Divine Heart of Jesus (I was an aspiring candidate there):
*O Sacred Heart of Jesus, You merit the desires and love of all the hearts You have cherished, loved and infinitely favored, and especially from my heart, which justly deserves Your indignation. But since You are a Heart of love, You are also a Heart of goodness, of which I will avail myself to obtain my pardon and reconciliation. O most sweet Heart if the sorrow and shame of a heart that acknowledges its error can satisfy You, pardon my heart, for such is its state through its unfaithfulness and carelessness to please You with its love.
Heart of my God, Heart most holy, Heart to whom it belongs alone to pardon sinners, may it please You to pardon this poor miserable heart. It gathers together all its strength in deep humility to make you amends and honorable reparation. O adorable Heart, how could I treat You thus, and withdraw form the Heart of my Jesus, Who without needing me had first loved and sought me? Renew my unfaithful and inconstant heart, and grant that for the future it may draw me near to You, as in the past it was far from You. Amen.*