Lip trills engage the breath-voice connection fast. The resistance at your lips creates back-pressure that cushions your vocal folds, letting you warm up without collision stress. You get breath control and range work in one move.
Start at 200 BPM. If your trill cuts out, press your fingertips into your cheeks to keep the vibration going. You'll feel a steady buzz across your lips.
This pattern climbs to the fifth, drops back down, repeats, then outlines a major triad on the way home.