I've just started reading lesson 1. Looking at figure 1-6, two things jump out at me about stretching at the end of dance classes.
1) The top position looks like something we often do seated on the floor (sometimes the instructor will say to use a flat back, and sometimes she will say to round it) though usually with more stretching towards the feet (either straight ahead to both feet or out towards one foot with the legs spread apart).
2) When we get up from the floor after stretching, the instructors will often tell us to stand up slowly, unbending one vertebra at a time with the neck coming last.
Are these practices to be avoided at all costs, or are they ok?