"How does third series feel up to this point? Are you exhausted after it or energized like after a Primery?"
First, I never thought that I would come that far. I thank M for this, because it's much fun to learn new asanas, a new series. In Ashtanga yoga we play with our limits. And push them. I'm so glad that he doesn't stop me only because I'm not able to perform every asana of second series. It will take years till I'll be able to do kapotasana i.e. But why shall I be stopped, I do what is possible and reach my limit. For me a coach/yoga teacher shall support the aspirant, not stop them and limit them.
A key sentence by myself: What one practices one will be able to do one day. If one doesn't practice anything one will never be able to perform it.
Of course this must be reasonable. If a student is not at all able to take the leg behind the head it makes no sense to start third series.
The asanas of third series seem doable. A few asana of third series I might never be able to do, let me mention gandha bherundasana. I don't want to limit myself, one can always work towards it. 98% of the asanas seem doable after years of practice.
When I practice third series asana after second series, I have to convince myself before every pose to do the next pose.
When I practice it after the standing asanas, the body is not yet really soft. Third series asanas require a much larger flexibility of the hips than the series before.
Repetition, visualization, additional exercises might be methods to progress.
Ashtanga yoga has always asanas that challenges us, asanas that make us modest. It's even a bit embarrassing how lousy it looks how I perform the first asanas i.e.. But I know to exercise it is what I can do how lousy it might be in the beginning.
I want to learn third series. A side effect: it makes look second series easier.
In fact primary became easier when I was able to go through second series. I experience already the same effect on second series.
A challenge: after the 7 third series asanas back bending is very difficult. This is why M changed the order for me (temporarily). I do the 7 headstands at the end. They prepare urdhva dhanurasana. It helps
I feel modest after having practiced the few third series asanas. It's about applying the techniques and observing what will happen. I must practice carefully, injuries seem possible. Being patient is important.