This three part series I will dive into the breath practice or pranayama called breath awareness. This is a breath practice that should precede all other breath practices. It helps lay a foundation for any breath practice you might do in the future. In this third part of the series, we practice refining the exhalation through an exploration of what it feels like to breathe out fully with diaphragmatic breathing, contraction of the abdominals, engage mula bandha, and costal breathing.

This information mostly comes from the book Teaching Yoga, Essential Foundations and Techniques page 247.