I take my reasoning from Hebrews chapters 3-10.
We could all pick out individual sentences in these passages to support certain ideologies; but as Paul himself says these things are difficult to understand, 'on this subject we have many things to say and they are difficult to explain because you have grown so slow at understanding…no one who is still living on milk can digest the doctrine of saving justice, (Hebrews 5:11-13), Paul obviously asks we reflect deeply on these passages of scripture.
God is not subject to either time or substance. Jesus took on human substance and entered time when on earth and in doing so, he placed on himself human constraints. When he rose body and soul to heaven, that is no longer the case. As his body and soul entered heaven, so did his blood which is now living matter in the eternal sense on the altar of God. It is no longer poured out in the human sense, the bloody manner of the cross, but in an eternal sense. His body did not see corruption, it is incorrupt in heaven, that is what Paul is explaining. The sacrifice in heaven is not bloodless, but it is bloodless in the human sense and Christ does not have to die over and over again. He does however offer his blood as our high priest and during the Mass, we commune with that offering.
'He is a priest for ever of the order of Melcizedek
He has entered the sanctuary taking with him …his own blood having won an eternal redemption