Here is a principle of bel canto that few hear about. "That which is by nature weak must be made strong, and that which is by a nature strong must be made weak." Inasmuch as this rule is operative in your study, you are using the stimuli of pitch, intensity, vowel, duration, and timbre to subdue tendencies that would master you if left unchecked. For the female, a major triad begun at b below middle c, sung on the vowel "ee," can be a powerful tool. Sing the root and third staccato and firmly, the fifth, staccato and pianissimo. It is a classic exercise of the bel canto. The fifth, which might otherwise be sung aggressively, is held in abeyance by both intensity and vowel, "ee" being the vowel associated with head voice, the strong made weak. Intensity and vowel may be powerful tools of your pedagogy, the exercise itself doing the work without your overt interference.
This post was written by Alan Bowers