Etymology and meaning of the word "pizzled"

I heard of a term today called "pizzled" and am confused about it as there is a plethora of different definitions for the word.

I first heard it in a speech by David Shing TNW Europe Conference. He said that it was a combination of "pissed" and "puzzled." I immediately thought it was made up and that it is new slang.

But then after further investigation I found traces to a short story where it was used in a strange way in 1955, see here: http://en.wikipedia.org/wiki/Autofac.

In addition, Wikipedia said "pizzle" is an old english word for penis, see here: http://en.wikipedia.org/wiki/Pizzle. In addition Wiktionary had the following: "Having the penis in a different tincture than the rest of the body."

What is the etymology and meaning of this strange word?

It isn't new but you are right, it is confusing. Interestingly, it is used in medical slang (Dictionary of medical slang -Jacob Edward) and it is defined as exhausted, or to its point:

Pizzle chewer ... A female who relieves a male of his phallic tension by fondling the instrument in her mouth.

Pizzle-grinder ... 1. A butcher. 2. A prostitute.

Pizzle honker ... A prostitute who satisfies her patrons by manual friction.

Pizzle warmer . . . The pudendum muliebre, esp. the vagina.

Pizzled . . . Exhausted physically or mentally.

Etymology: pizzle (n.) "penis of a bull used as a flogging instrument," 1520s, from Low German pesel or Flemish pezel, diminutive of root of Dutch pees "sinew," from Old Low German root *pisa.