source ：https://himandhersex.wordpress.com/2012/06/06/topic-14-sounding-urethral/amp/
Sounding or urethral sounding is the medical use of probes called sounds to increase the inner diameter of the urethra and to locate obstructions in it. Sounds are also used to stretch the urethra in order to receive piercing.
Urethral sounding and urethral play are also used to refer to this practice in a sexual context. Both men and women can participate in this kind of sexual play.
Urethral play can involve the introduction of either soft or rigid items into the meatus of the penis (as well as farther in) and the urethra of the vagina. Objects such as sounds are usually only inserted about halfway into the glans and can usually be easily retrieved. 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 in the male may be directly or indirectly associated with stimulation of the prostate gland and some types of bladder control. (wiki)
Urethral sounds/play, sometimes called sounding, is basically inserting objects (often steel sounds and catheters) into the urethra for erotic purposes. Sounds painful and unpleasant to most, but some people get a kick out of this. The pleasure or pain you’re asking about depends on the individual, but those that derive pleasure from sounding often get it from the physical or painful sensations, the psychological arousal, the power exchange, or pleasing their partner. However, people engaging in this play should most definitely have medical training, knowledge, education, and experience through mentorship as the risk of infection, physical injury and damage to the urethra is possible. (askmen)
In some cases, these scenes can be associated with people into medical scenes (playing amateur urologist hour), or in the BDSM scene, is closely associated with control and dominance. For the submissive/bottom, the psychological idea of being violated in such a manner, the inability to control bladder functions (if catheters are inserted into the bladder) along with the physiological sensitivity of the urethral lining can be quite a trip. For most people, the idea of urethral play is repulsive and dangerous, from my experience I find this to be untrue and wish to share some advice, opinions and suggestions.
In urethral play, you generally have two kinds of instruments that you can use. A sound is one type of device that comes in a variety of widths and is inserted into the shaft. Most people who are heavily into the use of sounds usually try to dilate or stretch the urethra, although there are many who get into seeing how far they can go as well. Sounds are sort of like wands usually made out of surgical stainless steel. Catheters are very different. A catheter is inserted into the shaft with the objective of reaching the bladder. Catheters are much longer and are usually made out of latex or plastic. Some types of catheters, like a Foley, have a small balloon that is inflated after it reaches the bladder. Once the catheter is in, the person who has it in pretty much loses control of when they can piss. There are many different type of both sounds and catheters. Many of the sounds are curved to follow the natural shape of the penis, while some of them are straight and forces the urethra to follow the shape.
Guidelines to Safer Play
* Do not use or take drugs that may deaden any sensations. Injecting lydocaine or any other topical anesthetic into the shaft is dangerous and won’t allow you to tell your limits (especially if your goal is to stretch out your urethra).
* Use water-based sterile lube to aid insertion of objects. Do not use lubes that contains nonoxynol-9 or any flavored lubes, both will irritate the urethra. Oil-based lubes are probably not the lube of choice, especially with anything latex, and also is more difficult to expel when you’re done.
* Be sure everything you use is clean and if possible, sterile… this goes more of less for sounds and other items inserted only into the urethra, not the bladder. Never use an unsterilized catheter or anything unsterilized if you plan on getting into the bladder.
* Encourage pissing after you’re done, this will help to clean out residues, dirt and any other small bacteria that may have come in from the outside.
* Even in hospital conditions infection is not uncommon. Should you get an infection, check it out immediately.
* In any BDSM, if you don’t trust the person doing it, don’t do it.
* Never flush or force any liquids into the bladder.
* Be careful not to let go of the sound when it’s inserted, once the sound is inserted more than 4 inches, the sound will usually rotate slightly and pull the rest of the sound down. Should the sound be totally inserted into the urethra and you lose grip, don’t panic and relax – the sound will come out naturally.
* Be aware that urethral play, no matter how carefully done, does irritate the urethra… so if you have any penetrative sex/oral sex afterwards, use a condom. (Actually, you should be using a condom all the time anyways…) (Contains explicite pictures)
Medical Sounding:
Figuring out how to insert sounds into the urethra is something that should be left up to the trained professionals. Inserting anything into your urethra just isn’t a good idea gentleman. Sounds were created to open up any blockages from the penis through the urethra. Without the usage of these sounds probing their ways to the urethra, the afflicted guy would find it painful if not completely impossible to urinate. Sounds are very thin, smooth, and metallic. Many of them have an s-curve at one end in order for the doctor to tease the blockages open. But, how do you get a sound into the urethra? Very carefully. That’s how.
Positioning. First things first. You can’t insert a sound into the urethra unless the subject is positioned correctly. Your subject has to be resting on his back. This is so you can reach the penis easier. Imagine trying to insert a sound into the urethra with your subject laying on his stomach. It would be pretty much an impossible endeavor.
Insertion. In order to get that sound in there, you have to make sure the penis is soft. It’ll make it easier to allow the sound to slide into the urethra. You are not to force the sound into the urethra. You’re supposed to let it gradually make it’s way to the urethra. The sound will be liberally lubricated before insertion is attempted.
Penal manipulation. One hand should be guiding the sound down the urethra. The other hand should be manipulating the soft penis. You see, you’re not actually pushing the sound down the penis hole, you’re actually moving the penis around the sound. Take into account the shape of the tip of the sound. You’re going to have to move the softened penis around the shape of the sound until you reach the blockages. The weight of the sound will be enough to open up the blockages. Remember, you don’t have to push. Let the weight of the sound cause it to slide down through the urethra. (mademen)
Female Urethral Intercourse:
Urethral intercourse refers to the penetration of the female urethra by an object such as a penis or finger. It is not to be confused with urethral sounding, the act of inserting a specialized medical tool into the urethra as a form of sexual or fetishistic activity.
The untrained insertion of foreign bodies into the urethra carries a significant risk that subsequent medical attention may be required. Documented cases of urethral intercourse appear to have occurred between heterosexual couples; a survey of the global medical literature available in 1965 reported accounts of thirteen separate cases.However, the stretching of the urethra required by this form of intercourse has also reportedly resulted in a complete and permanent loss of urethral sphinctercontrol (urinary incontinence); furthermore such intercourse would present a very high risk of bladder infection to the receptive partner.