Yichen. It is not a defect to turn more or less than the book says, sometimes you under rotate sometimes you don't. Dancing is not an exact science. Technique is to help you learn, but to much technique will interfere with the natural flow and movement of the body. Dancing is moving the body gracefully and flowing in harmony with the music. Your top may be stiff becacause your teacher is holding you to tight or you are trying to hard to maintain contact . Try to think of moving the top part of your body from the hips up as if they are floating on a cloud, stay into the floor with your lower body ,all the work in dancing is from the hips down. Your teacher is right ,you should concentrate more on the feelings that you experience when dancing with your teacher than technique. If my teacher talked to me like that I would be going else where damn quick. It's more important for couples to keep their poise and balance than always maintain contact, the contact should be light and not impead their movement. Doug