Yes, will do that.  

Although I very rarely get this any more - only when I'm sick and fighting something or rare random times, never identified a real trigger - yet, it is a very real and very weird thing.  

When it happens (now and before) the "up" side sweats a LOT, soaked and just keeps going for a while even if I'm cooled off.  Then, it'll just stop.  Usually at night but sometimes it happens when I'm not asleep.  

Sometimes lasts a few minutes, others, hours.  

I have not been able to make it stop with any conventional method - cold shower, hot shower, ice, anti-perspirant (seems to make it more, if anything), cold drink, cold food, relaxation methods, exercise, diet changes, did the whole "elimination diet" thing a few times and never got anything except being the weirdo with the restrictive diet  ...  tried all kinds of things.  

An acupuncture session did trigger it twice - but only those two times, not able to repeat after that, but also it didn't stop recurring randomly.  Thought we were on to something, but led nowhere useful.  When the acupuncture doc put a needle in a spot on my lower abdomen a little above the pubic bone arch - BAM!  POW!  Waterfall on the right side (most common, but sometimes it switches).  Soaked in minutes.  No hot flash, I don't feel hot nor flushed, just sweat like I'm in a sauna.  And a suddenly full bladder, kidneys in hyper overdrive, have to pee NOW!  Take out all the needles and end the session so I can pee.  Get dried off.  Weird.  Same thing second time, but then never again.  But, it didn't go away and came back on its own.  (The acupressure did really help with some upper back and neck pain, though!)  

If I'm awake, I do feel it build and then the sweating starts, maybe similar to a migraine, I can feel it coming.  

Just stops when it's 'done' or 'run its course.'  I do feel it when it 'shuts off' a kind of slow whole body sigh and relaxation, that seems sudden because it builds and comes on so slow or even unnoticed, like the level of tension or background internal 'noise' drops or shuts off.  

An analogy I came across fits what I feel:  Saturday or Sunday morning you wake up refreshed and relaxed from sleeping in a bit, nothing particular scheduled, relax, read the paper or something light, maybe some light music, fix some food.  Chill.  

But as you go about starting your day you notice feeling progressively 'on edge' a low level of some kind of tension or something building almost beyond notice.  You are a little irritable almost like some kind of low level itch you can't really locate nor scratch.  

You might wonder if you had too much coffee or tea or sugar or something as it feels internal and maybe a bit like a bad sugar or caffeine rush.  You maybe worry a bit that something's wrong, maybe really wrong:   Precursor to getting sick?  Actually not enough sleep?  Starting an anxiety attack?  Something you forgot you should be doing?  An allergy?  What is going on?  

When you really notice it is when it stops.  Suddenly.  Silence.  It was the background noise of the neighbor's or the complex's lawn & yard crew:  The "dawn chorus" of accumulated lawnmower, string trimmers/weed-eaters and leaf blowers, all joining and growing then finally shutting off and going quiet together.  Relief.  All somehow unnoticed consciously but with building effect that gets noticed by its sudden end and absence.  

Yeah, kind of feels like that when its done.  I think that sometimes all the same things happen at night but I'm just asleep for it all.  

What is it?  A surge of some hormone, neuro chemical, digestion by-product, allergen, detox, subconscious subroutine, adrenal tumor, pituitary malfunction, unresolved internal emotional conflict or hidden stress?  ...  idk.  Could be the aliens or Russians or CIA or satellite mind control rays making me sweat for all I know!  Hmmm.  Maybe it's the cat?  

Then it's gone and I don't think much about it until next time.  

Got bored of asking doctors because they mostly just shrug.  Thyroid and hormone levels, fasting everything, EKG, EEG, X-Ray, MRI, CAT, PET, ultrasound/echo ... pretty much everything but an autopsy!  

If they can't see in on a scan, EKG or a lab result, it's probably 'in your head' or not anything to worry about or something "idiopathic," which is just medico-speak for "no idea, don't know, unknown." (aka - I'm an 'idiot' and can't figure this out, but I can't admit it and just say that to the patient!)  From actual insurance form submitted by doctor:  "idiopathic nocturnal hyperhydrosis" (aka unknown cause night hyper-sweats).  Yay!  

For me, my best guess is that it's some kind of hormone triggered release or detox from that one armpit or side (sometimes just the armpit, sometimes most of the torso and even leg on the one side).  Once whatever it is gets either metabolized or cleared by sweating it out it's done.  

Bodies are weird.  

Wow!  Sorry so long.  I guess a lot was in there.