Water is root of Taanug:
Water is a compound that contains in it a great power of Taanug, pleasure. Although water in it of itself has no taste, nevertheless, it serves as the root of taste, and pleasure in all produce. All produce needs water in order to grow, and it is the water that serves as its source of pleasure. It is precisely for this reason that water has no taste of color, as it is the essence of pleasure, which serves as the root for all tastes and all colors. This applies likewise in the body, as the brain contains water based moisture, and it is this moisture which serves as the source of pleasure for the entire body. In marital intimacy, it is the moisture of the brain which iginites the passion and eventually causes the release of seminal fluid. The same applies likewise in the Sefiros of Atzilus, as all the pleasures found in Atzilus and lower worlds of Biya, all derive from the level of Aba, which is Chochmah, and is the spiritual level of water.
 Siddur Im Dach Kavanos Hamikveh p. 156; See also Tanya chapter 1 “And the lust for physical pleasures derive from the foundation of water, water grows all types of pleasure.”