The smooth muscle sheath which lies below the outer layer of skin.  The dartos fascia has involuntary muscle fibers that are temperature-sensitive. The skin of the scrotum contains these type of muscles, allowing it to contract or expand as needed to regulate the temperature of each testis. The outer layer of skin on the penis shaft and foreskin also has a dartos fascia.

Further or furthest from the center (of the body); opposed to proximal.  On the penis, it would typically refer to the glans or meatus.

The terminal branch of the pudendal nerve which connects to the skin of the penis, the foreskin, the corpora cavernosa, and the glans.

The outer layer of the skin.