my dad said the last thing he, and everyone else, did before climbing into the cockpit was to dig through all the clothing and pee....and it was the first thing they did when they landed. he talked about the relief tube but said with the several layers of clothing and the straps for the chute, dingy, and mae west by the time you wrestle yourself out to use the tube you were already to berlin and back. plus at 30k feet even with the heater blasting it wasn't all that warm. I have read accounts of 38 pilots using the tube and it freezing shut and overflowing. dad said by the end of a mission he could feel every thread in his underwear and his eyes were floating.....