What technique is used to produce the sound of a sort of pur or roll sound on a Soprano Recorder?

How do you make a pur or roll sound on a soprano recorder. Ex.) If you are familiar with the Good the Bad and the Ugly theme you know of the coyote sound or theme that is used for Eastwood. When the instrument plays and fades a slur out over and over again, you can hear a sound that feels like the tongue is slurring or rolling the notes or the air. Basically sounds like a feather or "pur" twirls, when slurred or sustaining the note. How can you produce this sound or technique with a Soprano recorder?