There have been occasions when I've been frantically trying to get out of a built-up area before I wet myself....then got a puncture. That was interesting. I think I managed to complete the job on one occasion, but on another I just had to pee up against the wall at the side of a used car lot.
It was just something you did - ladies tended to choose a wall or large bush and the men would all study the scenery in the opposite direction
One day walking on the South West Way, (at The Dodman if anyone knows it), I saw a woman crouching in the bracken looking for something she'd lost, or so I thought. Only when I was right alongside, and about to offer to help, did I notice she was having a pee.
'unscheduled nature studies' in that scrubby landscaping often found around industrial estates..
I recall peeing behind a skip full of rotting fruit & veg at the side of Doncaster market once.
I think I need a nappy these days. When the need comes on it is very urgent indeed. I get little or no warning.
I've found that releasing the pressure of the saddle from my undercarriage when I get off the bike often makes me want to pee. Before I learnt better, I'd find somewhere nice to stop and eat, then no sooner had I sat down and started a sandwich than I'd have to hastily pack up again, and scram.