It's possibly rubbing off something like the arm rest?
Mine are leather and I eliminated it by applying leather care cream, leaves them softer so they don't stick!
In your case, adjust the seat in several positions or turn up the radio
![signLOL :signLOL:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/signLOL.gif)
Those noises are a pain though in all fairness, I got one yesterday so I just closed the window and tried to block it out!