Common short term for the "protective cup" worn by male athletes playing
contact sports to shield their
delicate parts from injury. The cup is most often made of hard plastic, with a softer rubber or foam gasket around the edge for comfort. It may be somewhat triangular in shape, or contoured to curve from the
pubic bone to the
perineum. The former is good only against impacts from directly in front, the latter also guards against impacts from below/between the legs. Historically, a cup is worn tucked inside the pouch of a
jock strap designed to hold it (worn in place of common
underwear,) but in recent years, they sell
compression shorts with a front pocket that some people find more comfortable. Some cups made specifically for
martial arts are labeled to be worn on top of clothing, but this just looks silly, and might not protect the wearer as well as he thinks. (Getting hit with a
nut trapped under the edge of a cup may be more painful than the same hit without the cup!)
It's never been particularly cool to wear a cup. In sports with tight-fitting pants like baseball or football, it creates a silly-looking bulge. In spite of that, you used to wear it anyways, as common sense told you that however bad it looked, or however uncomfortable it was, that paled in comparison to being hit in the junk. Or perhaps your coaches enforced it with cup checks. (Taking a hit off your cup still hurts, but since the blow is deflected to the pubic bone, it's nowhere near as painful.) Nowadays, a lot of guys think they can react fast enough to avoid the hit, or it won't be that bad. Unless rules or coaches require it, almost nobody wears them in football anymore, and many pitchers and outfielders in baseball have abandoned them too. "I don't need it," they tell you.
An anecdote to counter that fallacy: Senior year of high school, my centerfielder (we'll call him "Eddie",) quit wearing his cup. His logic was that, as an outfielder, the ball took long enough to reach him that he had plenty of time to react to it. Midway through the season, he charged in on a hard-hit ground ball up the middle. It looked like he had it... until it struck a a sprinkler head, bounced, and hit him square in the nuts. To his credit, Eddie picked up the ball and threw it to his cutoff man before the overwhelming pain set in. The game stopped for about five or ten minutes as he writhed in agony in front of two teams and their attending parents. Including Eddie's.
The next day, Eddie started wearing a cup again. Don't be foolish. Nobody's perfect, and accidents happen.