Unfortunately there are poorly Catechized Catholics but thankfully I can help you and others who didn’t know.
The complete and definitive theological teaching of the Catholic Church regarding whether Christ Himself consumed the Eucharistic meal at the Last Supper relies on the highest theological synthesis approved by the Vatican, primarily formulated by Saint Thomas Aquinas in his Summa Theologiae (Tetria Pars, Question 81) and supported by Church Fathers.
Firstly, the patristic witness. The position that Christ consumed the Eucharist is rooted in several writings by several of the Church Fathers:
Saint Jerome in his Letter to Heibia (Ep. 120) explicitly provides the classic formula adopted by the Church, Jerome writes “The Lots Jesus Christ, Himself the guest and banquet, is both the partsker and what is eaten”
Saint Ephrem the Syrian in his Treatises 12:6 vividly writes of the event of the Last Supper stating “He ate of His own body and drank of His own blood, while He was pondering on the dead. With His own hands the Lord presented His own body to be eaten…”
Saint John Chrysostoms Homily 82 on Matthew notes to remove fear from His disciples when they heard the radical command of “eat my flesh” Jesus drank of the cup Himself to demonstrate that it was a holy and life giving action.
Saint Aquinas notes in Q. 81, A. 4 that if the Eucharist had been reserved or consecrated during the days Jesus was in the tomb (Holy Saturday), the bread would have contained only His dead Body and the wine only His Blood, because His soul was truly separated from His body at that time. But at the Last Supper, His body, blood, soul, and divinity were fully unified and consumed as one living reality.
Saint Aquinas defends the mainstream teaching using three core theological assertions:
The Law of the Lawgiver - Christ was the first to fulfill the commands He bound upon others. Just as He submitted to Baptism to sanctify the waters before commanding others to be baptized, He partook of the Eucharist to consecrate its reception before commanding: "Do this in remembrance of me."
The Nature of Sacrament - Christ received the Eucharist sacramentally but not to gain grace (since He already possessed the fullness of grace and divinity). Instead, He received it for spiritual delectation, experiencing the spiritual sweetness and joy of fulfilling the Old Covenant Passover types.
Perfect Communion - The head must share the same food as the members. By eating His own Body, Christ perfectly tied Himself to the mystical communion of the Church He was establishing that night.
Statue licking Catholics talk about Protestants multiple personal interpretations. Yet when you ask them “did Jesus eat himself” you get a multiplicity of answers!.
I thought, their infallible magisterium is there to keep this from happening.
🤷🏻♂️