The tiny adjustments on your Taiji positions or postures by an experienced master make a great difference on the inner effect of your practice. The slightest adjustment can make a huge difference that has to be experienced to be believed.
The internal energy increases rapidly followed by a huge amount of heat spreading and flowing all over your body. Your legs will shake and your body will sweat. Those effects are not easy to get from a book or video. You'd better attend a class and let the master adjust you in person by hand. These adjustments have to be patiently and consistently repeated until the student can replicate these adjustments for themselves. This takes a lot of time and effort, but will reap great rewards in the long term. It will also unravel the so-called mysterious abilities Taiji people possess. I will go further to say that this type of training is the key to unlock Chen Style Taiji from just being a beautiful form to being used in real combat. An old Chinese saying goes, "One adjustment by a high level master is worth three years hard training by yourself!" This is why in my class I always encourage students to stay in a fixed position after adjustments to experience it for themselves. Internal energy and feeling are so difficult to describe and there are many books which attempt to do so. It is much quicker to make the student feel it for themselves; I do not have to explain it to them. They understand completely by experience, not by reading hundreds of books. I open the door, the student must walk through by themselves.