Laxative
As a student (read: poor young person) I got roped into a medical trial at the university hospital. A mate who studied medicine convinced me it was essential for the advancement of humankind that the doctor folk understood the cells that line our colons. I sympathised with them greatly, especially since they were offering more than a month's worth of beer money to willing candidates.

On the day of the clinical trial, I was basically required to get up on an empty stomach at 6am, take a 3 liter bucket they provided, fill with water and dissolve a bagsy of powder. Laxative powder. Then I was to follow a steady schedule of downing the horrid stuff, tasted like watered down chalk. The taste was not nearly as bad as the effect: within 30 minutes I was on the toilet where I stayed for 3 hours. 3 hours of emptying my bowels and drinking horrible liquid that I knew would leave me very soon. Basically I was giving myself an enema. I imagined I was female and weeing. It didn't help.

That was part one. I then had to leave the comfort of my toilet and my house to bus it to the hospital. By the time I got there it was loo-o-clock again. The trial finished with an endoscopy: I watched on a monitor as my bum got closer, then saw the insides of my intestines. A little pair of tongs appeared into view, grabbed a fold of intestinal tissue and with a swift yank a sample was taken.

I spent another ten minutes shakingly drinking orange juice. Finally I went home with a fat CHEQUE and a 3 liter bucketful of good karma.

TL/DR: I did a wet poo and got a tube up my bum

EDIT: I spell pretty me
(Bosch balls, Wed 16 Jul 2014, 21:03, 7 replies)

This story would only be better if you'd shat yourself at the end.

( Amorous Badger NAKED BEA ARTHUR PHOTOS 4U, Wed 16 Jul 2014, 21:06, closed)

I had nothing more to give...
... but eerily odourless farts.
(Bosch balls, Wed 16 Jul 2014, 21:23, closed)

I used my imagination and I assure you that they did shat themselves. It was on the bus and it was on
a youth or an old lady depending on how sinister I want to make the conclusion.
( d.r._and_quinch when will you be famous?, Wed 16 Jul 2014, 22:26, closed)

+ accidentally in his own mouth

( 2 Can Chunder Word to your mums, I came to prod bums, Wed 16 Jul 2014, 23:47, closed)

One for the team!

( edjogs Collared doves are shit., Wed 16 Jul 2014, 21:53, closed)

bit gay

( 2 Can Chunder Word to your mums, I came to prod bums, Wed 16 Jul 2014, 23:46, closed)

Long story short, you pissed out of your arse and into your mouth.

( Muns, Thu 17 Jul 2014, 9:43, closed)