Well, I was having a few jars and jiggers with a professor friend tonight, and well into the evening the chat took a turn to where it was appropriate to bring up this thread. His comments on the "peter out" thing were most interesting.

His first explanation was non-phallic. He said that it was his understandinig the the expression actually is of biblical origin. According to that version, St. Peter was hauliing ass out of Rome, just tooling along the Appian way, escaping from a wave of persecutions and lion feedings, etc, when JC appeared to him and shamed him into returning to the city. His attempted escape became abbreviated to "Peter out". There is allegedly a church/shrine there today commemorating the site of the vision.

His second observation was that the word "peter" derives from a Greek word meaning "rock, implying hard."

I know not the truth of his comments, but we toasted his erudition anyway.