A clear, slightly gooey fluid produced by the bulbourethral glands (namely the cowpers gland) in human males. The fluid serves to lubricate and de-acidify the urethra for the impending deluge of semen. Also serves to remove any "foreign matter" from the urethra. Can carry residual sperm from recent ejaculations.
Michelle spit out Jasons pre cum because it tasted like piss.