Why here? This area is kind of like the Space Shuttle launch pad: it's where the fluids of ejaculation gather just before they take off up the shaft of the penis. When touched or massaged, the prostate - about a half-inch inside the opening of the anus - is a spot in men's bodies that heightens sensations during many a male masturbation session, including at the time of orgasm. You're certainly not alone in your discovery of rectal pleasure by stimulating the prostate gland and sensitive nerves around the anus - even if you didn't know that's what you were doing.
