The tricky thing with alignment cues in yoga is that not everyone needs to do the same thing for optimal alignment.
Some people need to avoid "tucking the tailbone" in poses, usually because they are already cemented in a kind-of-tucked-position which they need to get out of. And -- dare I say it -- other people need to go ahead and "tuck" a little -- a.k.a. move in the *direction* of a more-posterior pelvic tilt, relative to their starting place.
It all depends on the person in a particular moment, in a particular context.
And of course, the QUALITY with which someone adjusts means everything. Movements and adjustments (like "tucking" or almost anything) can be done aggressively and cheaply in an over-muscle-y way, and/ or without any sense of integration with the rest of the body, gravity, and the ground. Or, movements and adjustments can be done more intrinsically (using deeper muscles and smaller, slower, smoother, and with more contemplation and awareness), and with more integration in the whole body. Every pose is a whole body pose and every adjustment should come from some engagement in the whole body. And of course, without over-working. It is an art to be in the whole body, but not engage too much or work extraneously.
The point I would like to make here is about APPROPRIATENESS. If your sternum is already lifted, you don't need to lift it, even if the teacher says so. If all your weight is dropping into the inner heels, you might benefit from grounding the outer heels, even if the cue was to ground the inner heels.
We all have such different bodies with varied patterns, tendencies, needs, lives, energy levels, genetics, desires, and goals.
This is where discernment comes in. Hear something, and then ask yourself, does this apply to me, and if so, how much?
This is how you can go to a group class but help it work for you better. Just because a cue isn't right for you, doesn't mean it's a wrong cue. The challenge for teachers these days is to find cues that will help everyone work towards balance in their own bodies. This is difficult! But possible. This is one thing I help teachers with in my teacher training workshops. For example, "feel where the weight is in your feet. If you need more weight in the inner heels to feel balanced between the inner and outer, then ground there. If you need more weight in the outer heels to feel balanced between the inner and outer, then ground there."
Practice for your own deep nourishment.
That means practicing what you need. Sometimes what we need isn't comfortable and isn't our favorite thing, but we know it's healthy. And it doesn't always match what's right for your best friend or the general public.
And sometimes we aren't sure what we need. This is a HUGE part of it. I help people understand their bodies and themselves and what they might need. I give suggestions. It requires education and a lot of self-investigation. There's an assessment process. It takes experimentation. And it's worth the investment of time and inquiry.
Don't waste energy working vigorously in a direction you don't need. Let's get more streamlined. And more efficient with our time and energy. If you are working hard, ask yourself, "towards what?" And is that really what you need? Is it absolutely appropriate for YOU?
"It is not the degree of "willing" or "trying," but the way the in which the energy is directed, that is going to make the "willing" or "trying" effective." ~F.M. Alexander