Let's clear this up before it becomes even more murky.
The "g-spot" is the abbreviation for the Grafenberg Spot, which exists only in biological women.
In men, the prostate gland can produce a similar sensation to the sensation some women feel with g-spot stimulus. But there is no "male g-spot." Some people colloquially call the prostate gland that, but it's really confusing for everyone, so let's not do that, eh?
Men who want to stimulate the prostate gland can do so by putting deep pressure on the perineum or via anal penetration (with fingers, toys, or via male-male intercourse: please remember that anything inserted in the anus should have a flared base and be covered with a glove or condom).
For more on male anatomy and where everything is, please see: Man’s Best Friend – Male Sexual Anatomy
...and with that, I'm off to my morning boxing session.