A balloon-manipulating device for a balloon catheter, methods of making, and methods of use. The balloon-manipulating device includes a tubular body, a longitudinal hole through a least a portion of the tubular body, one or more balloon-compressing pieces of a sidewall of the tubular body, and one or more balloon-letting through holes through the sidewall. The longitudinal hole may extend from an opened proximal end of the tubular body to at least a distal end portion of the tubular body, and is configured for inserting a balloon-catheter shaft therein. Each of the one or more balloon-compressing pieces is configured for compressing a different portion of an inflated balloon-catheter balloon when the balloon-manipulating device is disposed over the balloon. Each of the one or more balloon-letting through holes is configured for allowing therethrough a different portion of an inflated balloon-catheter balloon when the balloon-manipulating device is disposed over the balloon.