For women, the G-spot lies directly behind the pubic bone within the front wall of the vagina. It is located about halfway between the back of the pubic bone and the front of the cervix, along with the course of the urethra. The G-spot is also near the neck of the bladder, where it connects with the urethra. The size and exact location varies from woman to woman. Imagine a small clock inside the vagina with 12 o’clock pointed towards the navel. The majority of women will have the G-spot located between 11 and 1 o’clock a few inches inside the vagina.  Most people have heard about this, but we still wonder — is there a male G-spot?
Where is the Male G-spot?
It is generally thought that the female G-spot and the male prostate are composed of the same tissue. The prostate is often referred to as the male G-spot. This might stretch the analogy a bit, as the area identified as the female G-spot is in-and-up behind the pubic bone. It also swells as the woman becomes aroused. 
The prostate, on the other hand, is deeper and resides at the neck of the bladder and in fact, is a valve that decides if the man is going to ejaculate or urinate. It is interesting to know that a male cannot achieve orgasm and urinate at the same time.
A lot of men are goosey about getting a rectal prostate exam by their doctor. However, there is nothing erotic about this experience.
With sexual arousal and in the course of sexual stimulation, anal stimulation is pleasurable only for some men. Some men also enjoy stimulation of their prostate, which does contract some during ejaculation.
You would have to push in deep into the rectum to reach the prostate, so some women or men with short fingers might not be able to get to it and reach the male G-spot.
If you wish to stimulate your partner’s G-spot, he should lie on his back, and your palm should be up. Make sure you do not have long or sharp fingernails because you could damage your partner's anal canal. Ensure that you have clean hands and be sure not to touch your own genitals with the finger you used to penetrate your partner’s anus because of bacteria that live there.
Remember that some men like prostate stimulation and others do not, just as some women love G-spot stimulation and others find it distracting. However, exploring and experimenting is fun for the majority of people. Unfortunately, there just aren’t any new and fantastic magical spots. Remember that human beings have been making love for millions of years so it is not likely that much has been missed during all that time until now. 
The Female G-spot
The female Grafenburg spot, or G-spot, is a region that, when stimulated, can produce intense pleasure and orgasmic response. It is found about one-third up the vagina, towards the front, and is often thought of as the urethra sponge. In men there really is no identical spot although in Men's Fitness US magazine, the authors allude to the male G-spot as the prostate gland. [2, 3]
As you have already learned, the prostate is found by placing a well-lubricated finger inside the anus. Once you feel the sensation of pushing against a walnut-sized lump, you have reached the prostate or male G-spot. Pressing or rubbing it creates an intense pleasurable sensation for most men and some refer to it as milking the prostate.
However, some people still feel very negatively about touching the anus. On the other hand, others claim that if a man wants to achieve extraordinary pleasure, stimulating his prostate is the key to a successful orgasm.
Since the prostate is located in an area where nerve endings are concentrated, it is easily aroused, often resulting in an intense orgasm. The female G-spot is an inch to inch and a half in size, but is one of the most sensitive vaginal areas.
Therefore, you must know that size matters not; knowledge, tenderness, sharing and caring are the ingredients for wondrous loving and climax. The myth that size counts is a myth discounted by most who know and enjoy true sexual sharing. Unlike the clitoris, which protrudes from the surrounding tissue, the female G-spot lies deep within the vaginal wall, and a firm pressure is often needed to find the location. Usually, the female G-spot is a lima-bean sized, spongy area which responds to stimulation by hardening and swelling as blood rushes to it.
How to Find the G-spot
The Sybian machine and typical vibrators, as well as a man who knows how to use his hands, can provide the maximum stimulation often required to awaken the G-spot. Moreover, it is interesting that it is not as deep as male prostate so most people can reach it.
Techniques for stimulating the G-spot are various. You could lie back with your knees pressed up to your chest. In this position, your vaginal depth will shorten and even small fingers should be able to reach the G-spot.
With a partner, lie on your side with one leg drawn up to your chest as your partner enters you from the rear so your partner should be able to hit the spot.
The G-spot responds to pressure rather than to touch, so gently stroking is not likely to get any results. It's more like massaging a pea under a mattress. One has to compress the flesh to find it. Try to insert fingers and bend them gently up. Do it around and behind the pubic bone.
Beyond the rather rough-surfaced tissue immediately behind the pubic bone, fingertips will encounter a very soft, smooth area. You need to go very slowly and let her tell you what she feels as you explore the smooth area, which will feel to you like the inside of a very slippery mitten so when you straighten your fingers and reach further inside, you will encounter a hard, rubbery structure. This structure feels like an erect nipple pointing south. This is the cervix of the uterus, and the G-spot is somewhere just this side of the cervix, about an inch beyond the mitten. It is somewhere in the flesh immediately in the front of the vagina.
It would be interesting if you could imagine that you are holding a tennis ball on those two or three inserted fingers. Then, an area about the size of a grape in the center of the tennis ball is what you are trying to reach. It can be anywhere along that two-or-three inch long area between the pubic bone and the cervix so explore it slowly. You must allow for feedback from the woman.
It would be best to let her guide your fingers with her words if she can feel the stimulation.
When you reach in from the front with the woman on her back, the heel of your hand is over her clitoris while your fingers hook around the pubic bone. Pull upwards, as if you are trying to lift her off the bed. Do this with the same sort of rhythm you would use with penetration, and keep your fingers hooked, so they press deep into the woman’s tissue. Once you know where it is you can try using your penis on it, but for a good G-spot orgasm, she may prefer your hand rather than penis.
In a face-to-face intercourse, the penis may not stimulate the spot enough to do any good, although some positions, such as the one where the women draws her knees close to her chest, may increase the changes for a G-spot orgasm, a very pleasurable feeling a woman could experience.
Techniques for Stimulating the G-spot
Men should learn the techniques outlined above very well if they wish to give pleasure to a woman. If the man wishes to explore his body and try something new, then the woman could give him something similar. However, some men do not want to try it and the main reason is they think it is something that only homosexuals are doing. However, that is not true, because each male has that sensitive area deep inside the rectum, to be more precise, on the front side of the rectal wall. If a man relaxes enough with a woman (or man!) he trusts, they could find his G-spot together. Sometimes, a woman’s fingers are too short to reach this area. Then you could try some accessories or sex toys.
Important Tips for Anal Sex
With anal sex, or stimulating the male G-spot, it is important to remember there are bacteria that live in the anus. These bacteria are different than the bacteria women have in their vagina. That is why you must be careful not to transmit these possibly harmful bacteria: vaginal sex after anal sexual intercourse is therefore not recommended.
If you are stimulating the male (or female) G-spot with a hand, you should wash your hands carefully before you put them in your vagina or mouth.
You should use a lubricated condom during anal sex. Moreover, you must know that the skin inside anal canal is sensitive and that bleeding is a common problem which could a transmision of bacteria into the bloodstream.
A fact is that anal sex is the riskiest sexual behavior for getting and transmitting HIV for both men and women and may also expose individuals to other sexually transmitted diseases or other infections. You can protect yourself by using condoms, pre-exposure prophylaxis (PrEP), post-exposure prophylaxis (PEP), and antiretroviral therapy (ART).