The one time I really experienced vertigo was when I was sitting on the floor of the aircraft, my legs dangling 'outside' the fuselage, actually in the ventral blister, and I was looking at the ground through the large bomb aimer's window. It gave the effect of sitting on the edge of a 4000 ft cliff.
Quite unnerving.
I still need a pee when at the edge of a cliff or tall building.