My friend, blood shaking my heart
The awful daring of a moment's surrender
Which an age of prudence can never retract
This may relate to a moment in Sir Gawain and the Green Knight. When the Knight appears at the Chapel Perilous, Gawain bends his neck—as per their agreement—in a daring surrender recounted in the poem as:
“Alle pe blode of his brest blende in his face”
“All the blood in Gawain’s chest blended in his face.” (line 2371)
But the lines could certainly also imply an erotic surrender—a giving in to temptation and desire—as opposed to a moment of physical courage or spiritual self-sacrifice.
To help improve the meaning of these lyrics, visit "The Waste Land" by T.S. Eliot and leave a comment on the lyrics box