Why blood?

Why not?

It is the kiss of nectar running through the veins of walking limbos.

Dance--and the blood moves.
Fuck--and the blood glows.
Rant--and the blood boils.
Lament--and the blood cools.

Watch the blood (or its vessels) for any length of time and you will
See that blood is the essence of Life while also the lodestone of the
Darkest Abyss.

This is called Awareness.

--The Tao of Razorwire Tantra, 5