What causes “piss shiver”?

Dear Cecil: What causes a person to shiver uncontrollably following urination (i.e., “piss shiver”)? My friends and I have wrestled with this for years even to the point of consulting medical authorities (they didn’t know either). We currently have two theories. One is the Rapid Heat Loss Theory which states that an uncontrollable shiver passes over the body following the rapid loss of several ounces of 98.6 degree liquid. This theory seems to have good face validity but as far as we can tell females do not experience piss shiver, which puts a hole in that idea. Our second theory is the Mini-Orgasm Theory, which states that a man’s penis is used for two major activities: urination and sexual activity. When a man urinates, the two functions cross briefly and he experiences a mini-orgasm that causes his body to shiver uncontrollably. Is either one of these correct, or is there a third theory we haven’t thought of? Pleae help, Cecil. Patrick Cormack, Dallas, Texas

Cecil replies:

I know I promised I wouldn’t answer this disgusting question, but my will is weak. Besides, the subject has been debated on alt.fan.cecil-adams off and on for weeks, and even though no firm conclusions have been arrived at (par for the course on the net), the least I can do is give an interim report. We’ve made progress on one front: someone came up with an impressive-sounding name. Peter H. M. Brooks proposes post-micturition convulsion syndrome, or PMCS. Sure beats “piss shiver.” Maybe now we can apply for a big federal grant.

The following key facts have also been unearthed:

Women — some, anyway — also experience PCMS.
That’s it.

Theory productivity has been a little better. Here’s what we’ve got so far:

Heat loss due to several ounces of warm fluid leaving the body. Maybe, but then why don’t we experience it during defecation, vomiting, etc.?
Heat loss due to exposure of the nether regions. Not likely; as one netter points out, babies snugly clothed in diapers may be observed to experience PMCS.
It’s caused by the passage of spermatozoa into the urinary canal. Guess that explains why it happens to women.
It dates back to pre-civilization days when men hadn’t learned to do their own shaking. Attributed to George Carlin. What a comedian.
It’s all the fault of the parasympathetic nervous system. The parasympathetic nervous system is up there with the Babylonians as the default explanation for anything you can’t think of a good reason for (e.g., photic sneeze reflex, closing your eyes when you sneeze), but I throw it in for the sake of completeness. Your mini-orgasm theory sounds like a baroque version of this.

End of transmission. Lame, I know, but what are you going to do? Cecil can’t figure out everything. I’d convene a special session of the Straight Dope Science Advisory Board, but they’re still sleeping it off from our last symposium. Contributions from the Teeming Millions cordially invited.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.