Santosha means Contentment. It is one of the Niyamas of the Yoga Sutras.
Contentment isn’t settling. Contentment is letting go of the attachment to getting what you think you should have; letting go of the sensation you get when you feel accomplished. When you attach yourself to the feeling of proud your pursuit of happiness becomes about that sensational emotion (stroking your ego) as opposed to actual contentment.
Contentment is being at ease with what you have, where you are and who you are. Contentment is a cornerstone of being able to meditate. Being able to concentrate is the first step toward meditation and that cannot happen if you have an unhealthy attachment to accomplishment.
This class includes twists and forward folds, sama vritti (even breath), and nadi shodhana (alternate nostril breathing), all of which promotes balance, evenness and calm.