Glad to help. Isn’t this such a great forum. I just finished practising some more slurs using passive air. This really concentrates on the corners to get the notes to speak, rather than cheating with a push of air. Do remember that in practise slurring from say low C to G in the staff, the inward movement of the corners is very small. More a sort of firming of the aperture corners with just a hint of movement. As John said in his post above “less is more”