The pump is designed to work gently without posing any risk to your delicate organs. However, some people apply too much pressure or pump for hours on end in attempt to speed up gains. In such severe cases, pressure can build up rupturing the delicate capillaries that supply blood to the penis. Another potential risk is that the wall that protects the erectile chambers which provide a rock hard erection. Luckily, with correct usage, there is 0% risk of injury.