I think it might be a reference to sodomy. As in you hit or "nock" the fart in the other persons anus with your penis.
Jimmy was such a phartnocker. On one occasion he nocked a fart so hard in Suzys anus that it backfired on his shaft.
by danny May 13, 2005
Get the phartnocker mug.by Iroically, it's Chris. August 7, 2003
Get the phartnocker mug.