This may involve directly painful activities, such as genital piercing , wax play , genital spanking , squeezing, ball-busting, genital flogging, urethral play , tickle torture , erotic electrostimulation , kneeing or kicking. Many of these practices carry significant health risks. Similar to many other sexual activities, CBT can be performed using toys and devices to make the penis and testicles more easily accessible for attack, or for foreplay purposes. A ball stretcher is a sex toy that is used to elongate the scrotum and provide a feeling of weight pulling the testicles away from the body. This can be particularly enjoyable for the wearer as it can make an orgasm more intense, as testicles are prevented from moving up. Intended to make one's testicles permanently hang much lower than before if used regularly for extended periods of time , this sex toy can be potentially harmful to the male genitals as the circulation of blood can be easily cut off if over-tightened.