How do I increase my flexibility to better position myself on the bike?

I feel my lack of flexibility is holding me back from having the ideal body position. That and when I try putting my head where the mirror would have been, my helmet rides over my eyes, so I can no longer see ahead of me, what should I do, apart from getting a new helmet.tThank you! via /r/Trackdays https://www.reddit.com/r/Trackdays/comments/bl0z3x/how_do_i_increase_my_flexibility_to_better/?utm_source=ifttt