A special plenary indulgence is available for Corpus Christi:
The faithful who piously participate in solemn Eucharistic procession, either inside or outside of a Church, especially on the Solemnity of the Body and Blood of Christ, may receive a plenary indulgence.
A partial indulgence is granted for visiting the Blessed Sacrament for adoration or for offering any approved prayer to Jesus present in the Blessed Sacrament.
The following acts will merit a plenary indulgence, should the conditions for a plenary indulgence be met.
Requirements for Gaining a Plenary Indulgence
1. Perform/recite the prescribed work or prayer(See below).
2. Worthily receive Communion. (Preferably, the day of the act or prayer.)
3. Say one “Our Father” and the “Apostles Creed”.
4. Say one “Our Father” and one “Hail Mary” for the pope’s intentions (the intentions designated by the Holy Father each month).
5. Make a sacramental confession within 20 days.
For a plenary indulgence, one must be free from all attachment to sin, even venial sin (or the indulgence is partial, not plenary).
PRAYER FOR GAINING A PLENARY INDULGENCE
Down in adoration falling (Tantum Ergo)
Down in adoration falling,
Lo! the sacred Host we hail;
Lo! o’er ancient forms departing,
Newer rites of grace prevail;
Faith for all defects supplying,
Where the feeble senses fail.
To the everlasting Father,
And the Son who reigns on high,
With the Holy Spirit proceeding
Forth from each eternally,
Be salvation, honor, blessing,
Might and endless majesty.
V. You have given them bread from heaven,
R. Having all sweetness within it.
Let us pray.
O God, who in this wonderful Sacrament left us a memorial of your Passion: grant, we implore you, that we may so venerate the sacred mysteries of your Body and Blood, as always to be conscious of the fruit of your Redemption.
You who live and reign forever and ever.
A partial indulgence is granted to those who devoutly recite the above verses. But a plenary indulgence is granted on Holy Thursday and on the feast of Corpus Christi, if they are recited in a solemn manner.