We took a WRAF ATCO on a Vulcan trip once. The rules didn't allow her to fly on a low level bombing trip, so it was a 5+ hour MRR boat-spotting bore-ex. Of course the inevitable question arose and she was briefed on the limitation of the crew relief facilities. The ever-helpful (?) ground crew suggested a large funnel, pee-tube and speed tape arrangement in the vis bomb aimer's area, but she simply said "Aren't these immersion suits supposed to be waterproof?".
We never did find out....