First, a bit of background. I've been training kungfu for nearly a decade now. During all these years, I had the nagging feeling something essential was missing. Shifu sometimes told me to follow tai chi classes as well, as it would make my movements more fluid. An opportunity to train tai chi with a good, proper trainer came up, and I took it. I learned a lot from that, which I incorporated into my main training as well, but that nagging feeling of something essential missing never went away.
During one class, the tai chi teacher lost his patience and told students off. He told me off by saying that I've trained for nearly a decade, but to him, I didn't train for even one day, cause I always leaned out of axis.
What this means is I pretty much move like the Tower of Pisa. I.e. my entire upper body leans over, while top of my head down to the hips (and actually to the bottom of the foot I'm standing on), should be in one line, straight down. To illustrate, here are some examples: I can do squats just fine. Cat stance and the likes are no problem. When moving from one stance to another where I have to do those, then stretch my leg out, I lean over. Same with doing kicks. When I do a front kick, my hips twist forward. That's how it should go. My back (lower and upper) should remain upwards, yet I lean backwards. This results in too much time lost getting back into position, taking most usefulness out of the kick.
That got me thinking... Shifu occasionally alluded to that as well, but was always very soft-worded about it. Because of that, I stupidly enough didn't pay much attention to it. When looking at the mechanics of every movement, keeping your back in axis is what makes or breaks it. As such, the tai chi teacher was right when saying it was as if I didn't train even one day.
Now the problem is: How to fix it? I've trained with this flaw for such a long time, removing it has become a real challenge.
Shifu told me to practice in front of a mirror, and during class he now pays extra attention to it and sends me close to a mirror when necessary. This works for static movements. Get into stance A. Check the mirror. Correct where necessary. Move into stance B. Check the mirror. Correct where necessary. This works fine for those static movements, but not for other movements, nor during more active movement (e.g. sparring).
This is where you guys come in. I'm hoping you can help me with some exercises that'll help me with this issue during active movement, and any movement in general. Especially useful are exercises I can do during daily life (e.g. when walking to the grocery store), as those aren't limited to designated training time.