Urethral Play
Urethral play is play that involves inserting objects into the urethra, and sometimes the bladder. 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...)
As I have said elsewhere here, there is not much direct pleasure-value in passing into the bladder because neither the bladder nor its sphincter were designed for pleasure. While entering the prostate chamber itself may cause pleasure, remaining there during an orgasm interferes with the load-and-shoot process of ejaculation and it is better to withdraw the probe from the sphincter into the safe zone of penis so that ejaculation can provide its natural pleasure. If the probe is not too snug (5-6mm is good for me)semen will pass by it with some back pressure which may add to pleasure.
When inserting the probe, go in un-erected and use only slight pressure. Rotating the probe will help ease it in and once you have passed though the curve, it will slide in easily. You will know when you have reached the sphincter because there will be slight resistance. You might want to rotate the probe again to ease it through. The sensation will induce the flow of preseminal fluid and once the sphincter has been opened for the first time, it will be easy to "stroke" it. Doing this while very gently stroking the full length of the penis with the other hand, (it will be erecting very quickly), will bring about an orgasm on short order, when you should extract the probe out into the safe zone of the penis as ejaculation begins.
The purpose of masturbation is excitement and it is possible to get carried away as excitement builds. You have to keep your wits about you while you are probing so as not to push too hard or deep or at a bad angle, which can cause injury. Control yourself until you extract the probe into the penis and then stoke the probe in and out in the safe zone while still stoking outside to keep the orgasm going and get maximum pleasure. Once you have finished ejaculating, you may want to pass the probe through the sphincter again for a little residual pleasure while you are still aroused, as your erection fades. And don't forget to pee after you're done to reduce the chance of infection.
Probing doesn't have to be an extreme-gonzo act of self-mutilation. It can be a very sophisticated and pleasurable masturbation experience. I have not had a partner do the probing. Like having her cut your nails, you have to coach ver carefully (as in avoiding cutting the "quick" of your nails) to avoid poking or stretching that will lessen your experience. I do fantasize of a pleasure girl with good skills and gentle hands doing this for me.