it’s just happening naturally without you thinking about it, so why not spend your practice session thinking about it…
first make sure you’ve found your sweet spot, that you are actually where you should be on it.
I did a video on this which might only be available in the Premium section. If you don’t have access to it then just experiment going from a small portion near the tip to an extreme point way down the mp…until it ‘s obviosly too far down (too much in your mouth).
At this point start rolling it back little by little until it feels like there is still a bit too much in your mouth.
The idea is to work at it until it doesn’t feel hard to play anymore at this new higher position.
We can’t develop a big sound with a very little bit in our mouth, it has to be quite a bit. And this sweet spot is different for all of us so experiment and give it some time.
this exercise will make you focus on your position and eventually you won’t be sliding down anymore….it worked for me!