A thick whitish fluid containing spermatozoa that is ejaculated from the male genital tract. Also known as Semen or Sperm. Unlike semen, spunk can also be used as a verb.
To say that someone "can't drink fog" is to say they're a lightweight at drinking.
It's history comes from many a Kerry man who has emerged from a pub after many pints, is suddenly hit by the air and immediately feels more drunk