During the 1999 eviction of the Crystal Palace protest site, I found myself up a tree, in a fairly tiny treehouse.
There were three of us in the same tree as 300 police and security guards stormed the site.
It was an interesting experience - hampered only by my own performance anxiety.

During the time we were up the tree, I had the urge to urinate on a frequent basis.
To perform such an action required the exiting of the treehouse through a door in the floor - carefully climbing down to a suitably sturdy branch, and hanging on.

I did this several times, and in full view of the surrounding police.
Unfortunately, I couldn't let the wee come out whilst being watched.
From the ground, it must have looked like I was simply 'showing off' and waving my tackle around for a few moments before heading back up the tree.

Luckily, when I was finally arrested, they didn't mention this.