to rock the diamondbacks

[kahroba]

Hi everyone
What is your interpretation for "to rock the diamondbacks that slept in their arms" in the following context from "Tar Baby" by Toni Morrison:

Wild parrots that had escaped the stones of hungry children in Queen of France agreed and raised havoc as they flew away to look for yet another refuge. Only the champion daisy trees were serene. After all, they were part of a rain forest already two thousand years old and scheduled for eternity, so they ignored the men and continued to rock the diamondbacks that slept in their arms.

 

[Myridon]

They were cradling rattlesnakes in their arms and rocking them like trying to soothe a baby.

 

[kahroba]

They were cradling rattlesnakes in their arms and rocking them like trying to soothe a baby.

Thanks a lot dear Myridon. You mean the rattlesnakes (diamondbacks) were sleeping in the arms to the daisy trees? What's the idea behind the figurative language?