I went looking for info and found these definitions in case any one needs schoolin like me
The glans: The head of the penis is keenly sensitive, the male counterpart to a woman's clitoris.
The coronal ridge: The ridge where the glans curves in to meet the shaft is a band of erotic electricity, particularly at the spot known as...
The frenulum: Found at 12 o'clock on the underside of the shaft, this fingernail-size spot is the center of his universe.
The raphe: This midline seam on the underside of the penis is exquisitely sensitive -- a zipper of nerve endings.
The scrotal sac: Gentle touching, please. You'll know you're doing it right when the scrotum tightens and contracts as if it were dancing.
The seminal vesicles: On the sides of the scrotal sac, the vesicles feel like little twigs. You can feel them turn rigid under your fingertips.
The male G-spot: To find it, search the muscular band of flesh that runs from the base of the scrotum to the anus for a slight indentation about the size of a dime. Pressing this dimple indirectly stimulates the prostate gland, as well as the inner base of the penis itself.