Greg Ladd screams at the TV every time he sees LeBron James doing it.
Or Tom Brady, Sidney Crosby or Landon Donovan.
Ladd is a big sports fan. He also is a dentist. And every time he sees a pro athlete who bites, chews or holds their mouthpiece between plays, he gets annoyed.
To Ladd, such actions mean their mouthpiece isn't the right fit and therefore is not likely to provide much protection. Even more, he says it sends the wrong message to youths who could end up emulating their idols improper actions.
"If you see someone sticking it in their sock or chewing on it between plays, it means it's a distraction," Ladd said. "It means it doesn't fit right.
"A good mouth guard is like a good pair of glasses. If it fits right, you don't realize it's there. You can breathe fine and talk correctly."
Mouthpieces - once found almost exclusively in football - are now common in most sports. Many athletes, however, are unaware of their biggest attribute. While they obviously protect your teeth, they also can play a big part in preventing concussions.
As football players finish up spring practice and then head to summer two-a-days, Ladd - who practices dentistry in the high school football hotbed of Dallas - hopes more will consider getting a custom mouth guard.
He's not the only one.
Eric Yabu, who practices dentistry in Oakland, teaches a class in dental trauma at UC San Francisco and serves as one of the team dentists for the Cal-Berkeley sports teams, says custom mouth guards are a must.
"Custom mouth guards as a whole are something that should be standard equipment," he said.
Correctly fitting mouth guards, Yabu says, help absorb blows to the head.
"It moves the jaw joint farther away from the base of the skull," he said. "It will prevent these jaw joints from pressing against the base of the skull and translating the force to the brain."
Yabu notes mouth guards won't prevent all concussions.
"If it's just a matter of hitting your head on the turf or a helmet-to-helmet hit, it probably won't do anything for that," he said. "I think it does help prevent concussions when the blow is coming from below."
Both Yabu and Ladd note that the standard boil-and-bite mouthpieces most kids pick up at their local sporting goods store provide little - if any - protection.
"Unless they are custom-made, they can look pretty but aren't going to do much," Yabu said.
They're not going to cost much, either. Therein is the biggest problem with mouth guards.
Standard boil-and-bite mouthpieces go for $10-$20. Yabu, who says he keeps his cost for a custom mouth guard around $100 as a community service, said $300 is a reasonable price.
That price point is one reason many don't have the proper fitting equipment.
Duxbury (Mass.) High has been making its athletes aware of the benefits of custom mouth guards for the past five school seasons.
And even though they have seen the benefits - and have found local dentists who will fit the kids for roughly $200 - athletic director Thomas Holdgate said the school would never make them mandatory. Mainly because of the cost.
"Kids already have to pay (a user fee) of $210 to participate," he said. "How much can you ask?"
And, as Holdgate points out, it may not be a one-time expense.
"An obvious issue you have is these are high school kids," he said. "They are going to lose them."
Holdgate said the school has taken numerous measures to protect against concussions. He credits football coach Dave Maimaron for pushing the custom mouth guards. The school uses the Maher mouth guards, one of many custom makers on the market - and the one that fits the nearby New England Patriots.
Mark Picot, an executive vice president with Mahercor Laboraties, says too much concussion talk centers on aftercare rather than prevention. He says his company can help, as the initial molding process examines the alignment of the jaw bone - then creates a mouth guard that makes sure the alignment is correct.
"We can determine, with this method, the probability your child will have a concussion," he said. "It is that simple - a five-minute process. We take upper and lower impressions. Then we mold a piece of wax on the teeth. Then it is fitted to align the jaw."
And best of all, custom mouth guards actually are comfortable to wear - allowing athletes to concentrate on their sport, not their mouth. And allow fans such as Ladd to better enjoy the game.
"Sports is all sensory, all sensation," Ladd said. "When you have a sensation distraction, then you're playing with it.
"I think they are better off with nothing than something they can't stand to wear."
-- RivalsHigh Senior Analyst Dallas Jackson contributed to this report.