Here is a simple flow to reverse the schlumped posture… You know, the one where we have sunk into a chair shape…
First stand up tall with shoulders squared. The tallest version of yourself!
Then arrange your arms into a goal post shape, where the elbows are pressing out wide from your shoulders and your fingertips point up. Really press those elbows wide to create a space in your shoulder joint.
Slowly pivot at the elbows so the fingertips point down. Flow between these two shapes.
Here are the cheats to avoid:
Going too fast. Things just get sloppy, so stay mindful and with the rhythm of your breath
Hunching your shoulders. Make this a true rotation at the shoulder joint
Flexing your wrist. It may feel like you are doing more, but its just cheating ;)