When you've been fucking for several hours, and a large quantity of sweat and grime has built up in your grundel region, this substance is called the essence of the Taint, or Tessence. It can be squeegeed off and used in a variety of ways, including personal lubricant, industrial strength solvent, pesticide, smelling salt, and others.

(noun) A successful type of theft which results in an acceptable, impressive and rewarding payday for the protagonist.