Here's a fun party game: give everyone a pen and paper and have them scribble down as many slang terms for "penis" as they can think of in one minute. When the time's up, you'll hear the obvious (various snakes, produce, hand tools) and the strange—"road flare," "oil derrick," "whipped cream machine."
Now for a doctor's contribution: "Your penis is a great barometer of overall health," says Kevin Billups, M.D., an associate professor of urology at Johns Hopkins Medicine. That's right: Your ding dong is also a bellwether for sickness. Heed its warning, and you just might avoid getting the shaft.