Definition: Penis (also known as cock) is men's external sexual organ. It is also the reproductive organ and is also used to excrete urine.
Men's penis is formed by three columns of tissue: two corpora cavernosa and one corpus spongiosum. This last part can be found in the bottom area (also known as ventral side), while the other two are place one next to each other in the top area (or dorsal zone).
The ending of the sponge body is elongated, has a bulbous shape and forms the penis glans. The glans is covered by the foreskin, a double-layered fold of skin which in adults can be retractable in order to reveal the glans.
Th bottom part of the penis, where the foreskin is subjected, is called frenulum. The semen is producen in the testicles and is stored in the epididimus. During cumshots, semen is ejected through the urethra.
Some examples of cocks can be found following the link
