After two minutes of watching me ride 'round on Delphi,
Jeff Moore said I looked like a "spastic Madame Defarge." (She's the knitting villain in Charles Dickens'
A Tale of Two Cities.) I'm glad to report that since receiving the benefits of
Jeff's clinic, I am now happily allowing my horse to self reward (I still need to make it an extra obvious reward) and thereby accomplishing several strides in relaxation! We've even achieved a relaxed shoulder in at walk. Progress!
Note the elbows down, shoulders wide and low, and stable core:

Keeping armpit muscles engaged, shoulders wide, and core stable; waiting for Delphi to give:

When she gives, I can then encourage her to self reward by uberstreichen:

Uberstreichen at canter:

Delphi relaxes her jaw, and I reward with uberstreichen:

"She is positively scurrying!" Note the improved suspension in the canter stride:

What a feeling! Thank you Jeff!