Urethral sounding

Urethral sounding is the practice of inserting objects (typically made by metal or silicone) into the urethra for sexual gratification. Urethral dilatation is a urological procedure that uses probes called sounds to enlarge the inside diameter of the urethra and locate obstructions in the urethra, or as a treatment for urethral strictures.

Risks
The insertion of foreign bodies into the urethra can present serious medical problems. If not conducted carefully, sounding carries a risk of irritation, tearing of the urethra, or of urinary tract infection. Infections may become serious if they progress to the bladder or kidneys.

Urethral play
Urethral play can involve the introduction of either soft or rigid items into the meatus of the penis (as well as farther in) or vulva. Other toys and items, such as catheters, may be introduced deeper; in some cases even into the bladder. Some items may even be allowed to curl several times or expand within the bladder. This action may be directly or indirectly associated with stimulation of the prostate gland and some types of bladder control. In women urethral sounding can lead to clitoral stimulation.