Kan & Li
Blending Water and Fire
Introduction
The simplest description of water & fire is that, in a person, usually the fiery energies are above - and tend to burn out through the top, and that the watery energies are below - and tend to leak out the bottom. In the kan & li practices, the fiery energies are brought under the watery and a kinder blend occurs. The water is refined and raised - and is less likely to leak, and the fire is nourished and anchored - and is less likely to flare.

the usual: fire over water the blend: fire under water
While the practices do start out as simple and distinct as that, the blending continues over and over; richness and subtleties continue to develop and emerge.

Essays, References
The Taoist I Ching by Thomas Cleary
Contains explanations of the trigrams for water and fire (pg. 22 of the introduction), and of the hexagrams for fire over water (hexagram #64) and fire under water (hexagram #63).
Tsongkhapa's Six Yogas of Naropa by Glenn H. Mullin
The classic text, from the Tibetan tradition.
S.Biel's Fire and Water technique.
This is a gentle - yet profound - way to integrate the heart and sexual energies, that doesn't produce the pressures in the body that Kan & Li proper does.
"Lesser Kan & Li" and "S.Biel's Fire and Water Technique" comparison.
a simple, yet deep, breathing method.
From HT-USA Discussion site post #5439, Title - Re: Kan & Li, Fusion and the Tiger and the Dragon
Lesser Kan & Li (suitable for viewing on-screen, 88k):
Lesser Kan & Li (suitable for printing, 108k):