I think this story must come from about 1984. Just before my home standby finished at 1800 I was called in for an urgent flight from Aberdeen to the Valhall Platform in the Norwegian Sector - it was in the middle of the North Sea and about equidistant from coastal airfields such as Aberdeen, Stavanger, Esjberg, you name it, it's equidistant. Like FED's story above, the task was to take an urgent oil tool to the platform and all but the front row of seats was taken out and the freight loaded.
We then had to wait for a passenger with specialist knowledge of the freight and he was on an inbound scheduled fixed wing from somewhere abroad, I forget where that was. Because of the urgency a tarmac transfer was agreed with Customs and as soon as he got off the fixed wing he was whisked into our helicopter which was now turning and burning alongside. A quick change into his survival suit, a brief from us, and we were on our way.
After about 30 minutes the passenger tapped me on the shoulder - he was desperate for the loo and not only that he meant for number twos!!
It was now around 2200, no platforms or rigs were in the vicinity, so I had to say we couldn't do anything for him.
A few minutes later he moved to the back of the cabin behind the freight, laid out a towel on the floor from his bag and proceeded to squat. He then wrapped everything up in his towel, left it there and moved back to his seat. Poor guy, I felt really sorry for him but we did not have a very pleasant flight onwards to the Valhall.
We had to stay the night as in those days Aberdeen closed at around 2230. It was my first experience of staying overnight on a Norwegian platform. What a palace compared to the British platforms!