When hip thrusting, the goal is to lift the barbell vertically without generating any rotation in the barbell. Rotation can be caused by excessive motion of the pelvis, pushing the barbell away from the pelvis towards the thighs (very common) or not lifting the barbell vertically but diagonally forwards or backwards. All of the above make the hip thrust less effective and efficient. Hipsarmour might slightly rotate while you perform the movement with incorrect form, giving you instant feedback of how well you are executing the exercise. When there is no rotation involved, you can feel your glutes working harder, making the exercise more effective.