Wrong. The phrase "piss shiver"returns 1,810 hits. The phrase “piss shudder” returns only 25 hits. Searching on those words without the quotes is meaningless to this discussion. And you were the one who started the whole thing by citing the definition of ‘shudder’, so yes, it is relevant, since practically no one uses that term to describe this phenomenon.
I think I’ve reviewed the bidding:
Alex, I certainly don’t see anything all that disgusting about pissing (In the proper venue), but you have made me consider something else. I’ve frequently gotten a quite similar shiver when I’ve been intent on some task and somebody has walked behind me unexpectedly. I’ve always attributed that to instinctive fear of surprise/ attack (a classic sympathetic response?). I daresay, that’s happened when I’ve been standing at a urinal intent on pissing. You are certainly in a compromised position and not in your primie fighting stance when you’re standing there with your junk in your hand(s), trying to spell your girlfriend’s name. I could go for an element of fear causing the shiver.
As for it being God’s method of shaking off, I can’t think of a reason why he would care if we shook off. And the youth angle is perhaps interesting, also.
As for the hypovolemia, I obviously shouldn’t be tossing around medical terms with which I am not expert. But is there no direct relationship between volume and pressure in the human body? Certainly the body can correct for volume or pressure changes within the body, but is it always instantaneous and is it always reliably consistent? The vast majority of the time, I never get piss shivers, but I occasionally do. That’s what the whole discussion is about. And how does the body correct for low volume/pressure? Is’nt it by constricting bloood vessles to bring up the pressure?
And why did I see so many people pass out after donating blood and while urinating?
I’m struggling to find a source that head-on discusses shuddering caused by emotion. The sources I find seem to keep dealing with the English language. To quote another dictionary, the OED defines shudder as “a convulsive tremor of the body occasioned by fear, repugnance, or chill.” MomboCat just talked about shuddering from fear, although I don’t think I’ve experienced this myself.
Now like I said, I don’t think of me urinating as being revolting. But come on… it’s not exactly the complete opposite of revolting either. If you still disagree, let me piss on you to prove my point.
Now, can anyone help out to find a modern-day discussion of shuddering in connection with revulsion and/or fear? Why is this phenomenon seemingly completely ignored, by science and by the public?
Why? I can’t think of a reason to believe they’re related at all.
Really? You can’t think of one reason? You can’t think why they might be related at all? Not even, say, that they’re both involuntary tremors of the body? You can’t think of it maybe because you’re not thinking. But thanks for taking the effort to write a post. Very constructive. Just like this one. Sigh.

With the piss shiver there’s a sudden decrease in blood pressure due to blood filling the body space previously occupied by the full bladder.
But as the bladder deflates, doesn’t the abdomen just shrink back in a little? I don’t see any reason why a significant void would form at all, let alone be able to be filled with blood, if it did.

Now like I said, I don’t think of me urinating as being revolting. But come on… it’s not exactly the complete opposite of revolting either. If you still disagree, let me piss on you to prove my point.
I still disagree, but I’ll beg off on the fetish play. I might mention in passing though that there are people who will pay for such services. I’m guessing you could find them using your proficient google-kwon-do.
In a more rhetorical vein I might ask whether spitting is revolting?
Or, is there some acceptable way to determine if there has ever been a person who experienced a piss shiver despite being of the opinion that urination is not revolting? (I’ll assume that my own anecdotal testimony would not suffice.)
I know you’re begging for a fight on your terms, but I don’t think working toward a clearer definition of the word, shiver, is really accomplishing much. Maybe if we used the term little Ed used: post-micturational frisson.

Now like I said, I don’t think of me urinating as being revolting. But come on… it’s not exactly the complete opposite of revolting either. If you still disagree, let me piss on you to prove my point.
That’s just silly. Changing the context can make lots of things disgusting.
A cigar isn’t revolting and a fried egg isn’t revolting, but a cigar stubbed out in the yolk of a fried egg is (IMO).
A mouse isn’t revolting - a mouse trying to climb in your mouth might well be.
If you shudder when someone pisses on you, that may well be from revulsion, but that’s pretty meaningless and irrelevant to the question of why people sometimes shiver when they pee.
i think the first time i gave the subject any thought was around the time i was first starting to learn the very basics of evolution in 5th maybe. i had a vague theory that it was an evolutionary trait specifically tailored to help shake off that unholy last drop that always seemed to end up in your boxers somewhere if you were in a hurry. and then i got to questioning just how such a small luxury would aid in survival or procreation.
another possibility came to mind when i saw just how easily piss cuts through feet deep snow: perhaps the loss of heat from 500ml or so of liquid leaving your body within maybe 30 seconds is significant enough that it would cause a brief shiver in your body to burn some calories like when you’re cold? i feel there may be a correlation between the amount of urine and outside temperature to the intensity and frequency of piss shivers.
I’d say the pissing -> revolting -> shuddering chain isn’t conscious, it isn’t even ‘sub-conscious’, it’s reflexive/instinctual. So it doesn’t matter what you think of urination.
Maybe it’s a form of communication, so the other animals know you’re pissing. Maybe it’s not even that the animals want to know when you’re urinating, but they want to know when you’re pissing on their turf. In general, people who shudder a lot are seen as dirty, disrespected people. Just think of Kramer. Or an alcoholic. I know I feel pretty dirty when I’m sucking down phlegm and shaking to boot.
Whatever we might speculate the purpose of shuddering to be, I know that the experience of piss shiver and other instances shuddering feel identical (like when MomboCat said piss shiver feels identical to fright shudder). I also know that shuddering is a world often unexplored by discussion on the topic of piss shivering. In fact, seems like everyone’s forgot about shuddering!

In general, people who shudder a lot are seen as dirty, disrespected people.
Universally? By everyone?
The whole “Pissing is revolting” argument is absurd. Taking a dump is a whole lot more “revolting” and I’ve never heard of anyone shuddering after doing that.
My own pet theory is exactly the opposite - I think that one shudders after pissing because it’s pleasurable, just like one might shudder if stimulated by a feather-light touch on the skin.
another possibility came to mind when i saw just how easily piss cuts through feet deep snow: perhaps the loss of heat from 500ml or so of liquid leaving your body within maybe 30 seconds is significant enough that it would cause a brief shiver in your body to burn some calories like when you’re cold? i feel there may be a correlation between the amount of urine and outside temperature to the intensity and frequency of piss shivers.
Not a bad idea, but I don’t think it’s likely to be this.
When you’re bladder is full, the contents are at approximately core body temperature - when you’ve emptied it, everything that remains is still at that temperature. You haven’t actually lost any heat in the sense that anything has significantly cooled down inside.

I’d say the pissing -> revolting -> shuddering chain isn’t conscious, it isn’t even ‘sub-conscious’, it’s reflexive/instinctual. So it doesn’t matter what you think of urination.
In which case, the term ‘revolting’ is inappropriate. How can someone find something revolting, and not know it at all? It’s nonsense.

Taking a dump is a whole lot more “revolting” and I’ve never heard of anyone shuddering after doing that.
I had thought about this myself — no one’s ever heard of a shit shiver — but there is the phrase “Shiver me timbers.”
I did some research however and found no connection to poopie paroxysms.

…When you’re bladder is full…
Missed the edit window by half a day, but I just wanted to note that I’m not such a dumbass to have written it this way on purpose. I mean, I might be a dumbass, but not for this particular reason.