I move my very upper body a little bit (Mid torso to shoulders) and I look around the bend so my head is always pointed to the end of the corner (god knows how it looks to others!)

As for my bum, it rarely moves to be honest, sometimes I have a shuffle round on bends, and went through of phase of moving my ass to either side of the seat in bends, but in all honesty I was concerntrating too much on my bum been in the correct possition and ended up messing the corner up as a result, so I just gave up.

You are doing Cornwall correct? Feel free to follow me and see for yourself.