I have one student currently tackling this movement and a few others who are within a few lessons of learning it. This is an exercise that really is the first one where we just feel our way forward until one 'feelage' really is the right one. Even on a perfectly schooled horse, shoulder-in requires so much tact the first few times, you know? It's like when we learn to post - we use every muscle in our bodies and it's straight up exhausting. But then we refine our ability to post and rely on…