Blood of vertebrae
In ancient times, people gathered to make a vow, killing cattle and taking their blood in their mouth or smearing it on their lips to show sincerity.
Idioms and allusions
It comes from "Yan Zhenqing Lun" written by Hou Fangyu in Qing Dynasty: "there are no loyal officials in the 24 counties of Hebei Province. The only one Duke of Lu stands up to fight against the bandits
Discrimination of words
Usage: used as predicate, object, attribute, etc
Blood of vertebrae
the most uncommon years and months of one 's life - suì yuè zhēng róng
make friends with congenial persons - hū péng huàn yǒu