The G spot is also known as the "Grafenberg" spot and is named after the doctor who "discovered" it. It is 1-2 inches on the front wall of the vagina and you can cause it to orgasm by vigorously trying "scoop" it out with your middle finger. You will only feel the G spot when you really turn her on. It feels ribbed like the roof of your mouth. It responds to pressure (not touch) so you have to be quite firm to stimulate it. There is also a key step you must do to set the right conditions for the G spot orgasm.
You literally have to train the G spot to respond orgasmically to your stimulation. Do not rely on the woman to train herself. Sometimes you may get a sore wrist, but it's well worth it. You'll even get to the point where you will make her ejaculate out of her urethra. This is not urine. It is female ejaculate. It is watered and slightly milky in color.
Most "experts" only give you an anatomy lesson of the G spot. But, do not you want to know HOW TO stimulate it to cause an orgasm every time? There has been a big debate about whether or not the G spot exists because some doctors found it but some doctors did not. The G spot is like an erection: you will only find it when the women is personally aroused and it will be obvious. There was even a debate about whether or not the female orgasm actually exists. What a load of garbage. These men did not want to acknowledge that they could not give women orgasms so they tried to convince women that the female orgasm did not exist so they would not have to perform like real men.