OK, since you're interested I'll explain. As a disclaimer, this is for information only and I am not suggesting that you actually do this (or anything else for that matter).
I've done urethral stimulation with a number of patients during medplay exams. The great majority of the ladies who have tried this have loved it, and in post-exam follow-up reviews it's almost always mentioned as a favorite. The stimulation is intense. As woman's urethra is located adjacent to the internal tissues of her g-spot and clitoral root, so as something moves up through your urethra it stimulates those tissues too. Then inside at the entrance to your bladder is yet another errogeonous zone. It seems that one is the secret treasure you don't even know you have until you've felt it stimulated. My patients have told me that being stimulated there is as intensely erotic and effective as direct clitoral stimulation. It's that good!
You need to be extra careful with urethral play. I cannot overstress the need for impeccable cleanliness. Your vulva, hands, and anything you will insert or might touch must be sterile. Anything you insert must be long enough so it cannot become "lost", unbreakable, easily sterilized and perfectly smooth. If you feel the slightest imperfection or burr (such as might snag pantyhose) on whatever you're thinking of inserting do NOT use it. If there are any sharp edges on the end do NOT use it. Additionally, you must use a lubricant. Stick with KY jelly (or generic equivalent) from a brand new unopened tube and you'll be fine.
You can do urethral stimulation with various items. If you've done some research here or elsewhere on line you've probably come across a variety of objects mentioned. My suggestion is that you keep in mind the "long enough so it cannot become "lost", unbreakable, easily sterilized and perfectly smooth" requirements.
In a real medical procedure the most common items used urethrally are catheters. There are various types and they come in a number of sizes. You can read all about them on Wikipedia. A link is at the end of this post. For simple catheterization and/or stimulation I like to use just a standard straight (Robinson) catheter. The most comfortable ones are clear plastic and listed as "hydrophilic".
There are medical instruments known as "sounds" that are used for urethral dilation. The cost is in the $70-150 range for a complete set. A suitable low-cost option is a set of aluminum crochet hooks. Of course you'll be using the handle end, not the hook end! You can find a good selection at Joann Fabrics and similar stores. Aluminum is best because the handles are extremely smooth and they can be sterilized. There are also steel ones that are very nice and equally smooth and sterilizable except they tend to be expensive in the larger sizes. At the end of this letter, I've included links to a couple sets that are around $10 and have the right sizes. I like the Susan Bates ones better because the tip of the handle is more rounded. If you would like to experiment you'll need a set of these hooks, a fresh unopened tube of KY jelly, something for sterilizing (I prefer hydrogen peroxide), some antiseptic wash and baby wipes, and two freshly washed bath towels.
1. You would start by sterilizing the crotchet hooks by soaking them in hydrogen peroxide in a glass or plastic container big enough so they can lay flat.
2. Wash your hands thoroughly with a good antibacterial soap.
3. I suggest that you preform the dilation and stimulation while laying on your bed, but if you prefer you could do it sitting on a chair. In any case you should have a towel under your pelvis and another one close by to set your sterile items on.
4. Take a baby wipe, squirt some antiseptic wash on it and wipe your hands. Use another one and wipe the outside of the tube of KY. Throw away the wipes. Set the cleaned KY tube on the towel.
5. Use another baby wipe with antiseptic wash and open your labia and wipe all the way from your clitoris to your anus. Repeat two more times using a fresh wipe each time. The last time you'll concentrate on the area of your urethral opening just above the entrance of your vagina.
6. Use another baby wipe with antiseptic wash and wipe your hands again.
7. Prepare another wipe with antiseptic wash. Remove the smallest hook from the hydrogen peroxide, shake off the excess, then wipe thoroughly beginning at the the handle end. Once it has been sterilized do not touch the handle end with your fingers. If necessary you can set the sterile hook on the towel.
8. Open the KY and squirt a generous amount on the last couple inches of the crochet hook handle and especially on the end.
9. Spread your labia and find your urethral opening with the end of the crotchet hook. Very gently begin inserting it. You should feel a weird sensation like you need to pee but absolutely no pain or stinging. It should go in very easily. You'll be guiding it in, not pushing it in. If at ANY time you feel ANY pain or stinging stop immediatly!!!!
10. As you insert the handle you'll feel increasing stimulation. As it gets about 2-3 inches inside your urethral you'll feel a slight resistance and even more stimulation. That means the end of the handle is at sphincter muscle at the entrance of your bladder. Carefully insert the handle about another 1/2 - 1 inch through that muscle. Do not insert the handle any deeper than about 5 inches (or beyond the point where it begins to widen).
11. Now you will leave the handle in place for a minute or two to give your urethra time to become accustomed to the dilation. You'll need to hold it inserted or it will slip out. You may wish the stroke it in and out but I would prefer that you wait until you're fully dilated. You may however rub your clitoris a little.
12. Once your urethra is dilated you'll feel less sensation from the handle and you are ready for the next one. Let go of it and wipe and lubricate the next size hook as explained previously. It's likely the inserted hook will slip out by the time you are ready to insert the next larger size.
13. Introduce the larger hook as previously explained, and then continue with larger sizes until you have taken the biggest one you have or feel that you can take. Remember - there should never be any pain!
14. Now it will be time for you to experience your first urethral orgasm. You will find that the stimulation is the greatest well up inside at the muscle at the entrance of your bladder. You'll achieve that by slowly and gently stroking the handle so the tip passes in and out through that muscle. Essentially, you'll be masturbating your urethra. You may also wish to rub your clitoris at the same time until you are close to a climax. However, for the maximum effect you should leave your clitoris alone once you feel your orgasm is just about to begin. Stroke the handle gently to put yourself over the edge, and continue as long as you are orgasming.
15. I recommended you have a towel under you because if you withdraw the handle while you are still orgasming there is a good chance you'll squirt. Or you might even experince another orgasm as you withdraw the handle.
A few other things. Total sterility, perfectly smooth dilators, and a extremely gentle approach are the keys to avoiding a Urinary Tract Infection (UTI). Those can be VERY serious. After urethral play you may feel some sensitivity in your urethra especially when you pee. It should feel normal within a day or two. If it doesn't go see your doctor because you might have a UTI. Don't be tempted to try any of the cheaper plastic hooks. They are not smooth enough, and even the slightest scratch could result in a UTI. Incidently minor imperfections and sharp edges can be polished smooth with 400-600 grit sandpaper. Don't ever insert the handle deeper than about 4-5 inches total. It's not necessary to take the biggest size handle. Do not use any one that feels uncomfortable. It might be a good idea to drink a glass of cranberry juice an hour or two before playing because there is some evidence that it helps prevent UTIs. Use KY jelly or equivalent only. Do not use vaseline and any other lubricant that is not water-soluble. You might find it helpful to use a hand mirror if you are having difficulty finding your urethral opening. You might also find it exciting to be able to actually see the handle inside you. If you are going to use a mirror don't forget to sterilize the mirror handle with the wipes and antiseptic wash too.
If you need any more information I would be happy to help. You can contact me here or by using docwellhung at yahoo. If you try this please share your experience. I would love to hear about it!
Links
http://en.wikipedia.org/wiki/Urinary_catheterization
123stitch.com/cgi-perl/itemdetail.pl?item=BOYE-6279 (Boye Aluminum Crochet Hook Set)
123stitch.com/cgi-perl/itemdetail.pl?item=C12196 (Susan Bates Silvalume Crochet Hook Set)
walgreens.com/store/product.jsp?CATID=304840&navAction=jump&navCount=1&skuid=sku361462&id=prod361461 (antiseptic wash)
Warm Regards,
"Dr. Wellhung"