126 Why then, Venerable Brethren, should we not approve of those who, when they receive holy communion, remain on in closest familiarity with their divine Redeemer even after the congregation has been officially dismissed, and that not only for the consolation of conversing with Him, but also to render Him due thanks and praise and especially to ask help to defend their souls against anything that may lessen the efficacy of the sacrament and to do everything in their power to cooperate with the action of Christ who is so intimately present. We exhort them to do so in a special manner by carrying out their resolutions, by exercising the Christian virtues, as also by applying to their own necessities the riches they have received with royal Liberality. The author of that golden book The Imitation of Christ certainly speaks in accordance with the letter and the spirit of the liturgy, when he gives the following advice to the person who approaches the altar, "Remain on in secret and take delight in your God; for He is yours whom the whole world cannot take away from you."
Source: Mediator Dei (Vatican.va)