When the skin of the back and the superficial soft tissues under the skin are lifted, a localized rattling sound occurs, usually due to the normal expansion of the soft tissue gaps. The superficial soft tissues of the body are very mobile, and the gaps can be large or small, and the superficial soft tissues are more flexible, so that the back lift can be performed. However, when the superficial soft tissue gap expands instantly during the back lift, it will cause the local fascia, fat layer, and subcutaneous layer to separate. Before the separation, the soft tissues are generally close together, and once separated, mild negative pressure adhesions will occur. Once the soft tissues are separated, the sound of negative pressure bursting will occur, resulting in a local popping sound. Although it is possible to have a more comfortable and pleasant feeling after the popping sound, this operation should be done as little as possible to prevent the emergence of local damaging inflammation.