I nearly always slide with my pinky - and then I struggle with control. (while writing this, I just realized that I should explore sliding with i, m, or r). Anyway, recently I've thought of reinforcing the pinky with the ring finger when sliding - I believe this is similar to the technique known as the Simandl approach for upright. Anyone use the r to reinforce p when sliding? I've tried it for the first time today and it seems like it helps sometimes, but it's still so new that it feels really unnatural. Anyone help me here?