If you want to produce a mind blowing orgasm during examination then brush up on anatomy. Also realize that this does not work the same, or even at all, for all women.
Starting with the clitoris - self explanatory and we all how that that works
U Spot - located very close to the skenes gland and urethra, basically just inside the vagina and brushing next to the urethra. A brushing strike along either side of the urethra ( think of this as an upside down "U" ) will get results - pushing or deeply palpating into this area is not comfortable...doesn;t work that way
G-Spot - located half way inside the vagina on the anterior ( top) wall. The clitoris extends deep within the vagina, not just the external visible tip, so you are actually stimulating the deeper sensitive part of the clitoris. If you are performing an internal exam, palm side of your fingers facing upward, curl your fingers back toward your external thumb. You'll find this "pocket" on the anterior vaginal wall and once found if you curl your fingers back and forth stroking that area you can usually produce a very pronounced orgasm...same principle that also produces squirting in some women
A Spot - A being the deep anterior part of the vaginal wall between the cervix and bladder. If you are giving realistic exams then you are familiar with getting your fingers deep into this area to move the cervix side to side...but where you want to go is on the anterior...top...wall above the cervix and deep into that crevice. You can also get a second finger under the cervix on the posterior wall but it's not quite as sensitive. You can reach the posterior wall better during a rectovaginal exam but lose the sensitivity of having a finger on top of the cervix.
Keep in mind that a good exam starts with the breasts and especially paying attention to the nipples - this releases a hormone called oxytocin, which in turn increases uterine sensitivity and etc. The A spot is a totally different critter and produces what folks refer to as a vaginal, cervical, or uterine orgasm. It's explosive, comes in waves, and most interesting is that unlike clitoral you can repeat this type of orgasm in succession with no need to take a break in between.
Getting to the above takes some serious effort on the part of the playdoc. Personally I incorporate this into a very realistic exam and work in the sexual health aspects ...all geared towards creating an erotic experience. If you incorporate this technique into a bimanual exam and go slow and deliberate back and forth between palpating the uterus and then the A Spot you'll hit gold. It's not my personal cup of tea but you can go the route of putting on gloves, inserting candy thermometers up the rear, and then just heading to basically what amounts to sex with props...you may get there this way, and all that is just fine if that's your thing. I'm just pointing out that getting to something with the A Spot isn't easy, involves the brain as a primary sex organ, takes slow deliberate build up, and you probably won't get there by shoving a couple fingers deep inside. The end result though is really worth the effort
Regards
Greg