you know you held on to long ..... you finally make it to the bathroom or side of the road,outhouse or where ever.you let loose and it feels better than an orgasm.been there done that. 
Well Neil, some would argue that if you think that, then you've never had a decent orgasm, but I agree mate. I was "out bush" a couple of weeks ago doing Army reserve training, and as we were "full tack" (fully tactical) I was sleeping under a "Hutchie", which is just a small camouflage ground sheet suspended about 18 inches off the ground.
Now for an old bugger like me it takes awhile to get in and out of my sleeping bag, which is enclosed in a seperate waterproof goretex "bivvie bag", so once I'm in bed, that's where I want to stay, particularly as it was pissing down rain and blowing a gale, and I'd just finished an 18 hour work-day. As it had been very dry and dusty I'd also drunk a lot of water and juice during the day and evening, and that was, in hindsight, a particularly bad move.
I woke up in the dark with a feeling of mild "pressure" in my nether region. Hmmnnnn. I tried to think of other things, like my 836cc engine rebuild that I'm doing this weekend, or how enjoyable it would be to own a fully stocked money bin like the one that Scrooge McDuck enjoyed so much, but the relentless patter of drops of rain dripping off my hutchie snapped me back into reality. I rolled this way, and that, and thought how amazing it would be to have a length of hose and a funnel right then, and after a half hour or so, managed to fall back into a troubled, painful sleep.
A dreary, water color dawn broke at around 0530 and as it was my task to "rouse" the troops, I crawled out of my toasty warm "cocoon", dropped my hutchie to ground level and moved a couple of yards from my little house and took an enormous, torrential pisss. No joke, it was possibly the longest pissss I'd ever taken, it went for at least 5 minutes, at full pressure, which I estimated to be around 5 litres per minute, while I stood there watching the early morning sun reflecting from the stream, creating a small rainbow of it's own.
I really thought I might turn inside out, I'd lost so much liquid. I had to keep moving further and further away from my hutchie, as I was worried that the torrent of urine would eventually flood it! Not only could I write my name in the mud, but the lyrics for Elton Johns "Goodbye Yellow Brick Road" album, and the first 3 chapters of Mein Kampf!
When it finally eased to a trickle and then stopped completely, I reckon I was around 40 pounds lighter, and like Neil, I was so relaxed, I felt like I should light up a cigarette and go back to bed!
