Dick is a common English language dysphemism used for a variety of slang purposes, some generally considered vulgar. It is also used to refer to the penis ,  and by extension as a verb to describe sexual activity. It is also used as a pejorative term for individuals who are considered to be rude , abrasive, inconsiderate, or otherwise contemptible. Variants include dickhead, which literally refers to the glans.
One man inserting his penis into another man's peehole. The holy grail of creepy internet porn. One of my worst sex nightmares is breaking someone's penis. The cracking sound, the discoloration, and, most likely, the screams are the stuff.