A friend was on a holiday with a touring caravan - continental make with door on the road side. A bursting bladder caused an emergency stop at the side of the road, and she shot into the van to use the portable loo in the tiny compartment near the door, Trousers down, lift lid, sit - then realised that she had previously stretched cling-film over the bowl as it had been primed with disninfectant fluid and she hadn't wanted that sloshing out en route.
Too late to put the brakes on, so rapid move in a squatting position to the door of the van to shoot a stream out onto the oncoming traffic.