What are some VERY effective streaches to do to get your splits quickly?

I am on my high school cheer team and the season starts in 2 weeks. my left and right splits aren't all the way down and my middle splits aren't good at all. I want my coaches to see that my splits have improved since last year by the time cheer starts in 2 weeks. Any advice on how to do this? Thank you for your help! :)