Been taking driving lessons, which are brilliant - I take them in two-hour slots, but I've noticed that I always get a pretty wet back every time I drive. I've tried shifting my position a couple of times, but the end result is the same. However, I've never experienced this as a passenger, even on long journeys. Am I just sitting incorrectly? Am I too tense? Is it the design and fabric of the seats (Corsa)? What is it??