A common instruction in yoga, material arts, dance, and other types of movement practices, as well as in rehabilitation therapy modalities is to tuck the tail (coccygeal vertebrae).
The heart is usually approached as a separate organ that pumps blood through the rest of the circulatory system. In my experience, looking at the heart as a pump puts stress on the heart.
Patterns of stress and trauma are usually approached through the nervous system—it can also be helpful to drop underneath the nervous system to the circulation of our blood.