COLUMBIA — He stares into the camera, forcing a serious expression onto his face.
Wooden lockers behind him hold jerseys and shoes. In front of each locker is a black chair with "Mizzou" emblazoned on the back cushion.
With a baggy Missouri men's basketball polo concealing his powerful arms, he delivers his message without ever allowing his tone to waver.
"I'm J.T. Tiller, Tiger guard," he says, sitting in the locker room. "If someone tries to pressure you to do something that's wrong, you can refuse."
It is Tiller's second time taping the public service announcement for the Missouri Division of Alcohol and Drug Abuse. This year, he refines his serious face.
"You can say no to alcohol, drugs or anything else that can hurt you," Tiller continues. "It's not that hard. It just takes a little practice."
Even when the camera zooms in on Tiller's mouth, there is no sign of his usual smile.
The commercial cuts to a clip of Tiller in his home jersey scoring in the lane against the Purdue Boilermakers last season. Then back to the locker room.
"It's your life," Tiller concludes. "Don't let alcohol or drugs keep you from being a winner."
Tiller needs only a couple takes to perfect his performance. The first time he taped the commercial, as a sophomore, the number of takes was more like six. After each failed attempt, Tiller laughed while the director implored him to stop grinning.
"It was very difficult," Tiller said.
Tiller speaks as if every topic brings a joke into his head. The corners of his mouth push his cheeks up toward his eyes. A few laughs often slip out between sentences.
Tiller means no disrespect. He's just happy.
Defense is, by its nature, reactionary.
The offensive player does something. The defensive player reacts.
But watching Tiller play defense is like watching a tornado. His hands and feet never stop moving. Tiller weighs on opposing guards, pressuring them until they make a mistake and then pouncing.
Missouri men's basketball coach Mike Anderson compares him to a "Tasmanian Devil," the cartoon character that spins and gobbles up everything in its path.
Tiller leads the Tigers with 52 steals this season. He also leads the team in Anderson's favorite defensive stat, deflections. Tiller averages more than five per game.
"He's our knockout blow. You throw a blow at us, we knock you out with J.T.," senior forward DeMarre Carroll said. "If you bring in one of your top scorers, we're going to throw J.T. at him."
Tiller has delivered that knockout punch to some of the Big 12's leading scorers. Baylor's Curtis Jerrells and Texas' A.J. Abrams each average more than 16 points per game. Tiller held them to 16 points total in back-to-back Missouri wins.
He saved his best work for Kansas' Sherron Collins, who is fourth in the conference in scoring. With Tiller applying pressure, Collins scored in single figures for only the second time this season.
After the game, Carroll interrupted a reporter to nominate Tiller for an award.
"My guy, he's got to get defensive player of the year, I'm saying that," Carroll said.
Tiller, never one for self-promotion, smiled sheepishly.
Anderson doesn't allow his freshmen to have cars on campus. It's a rule intended to keep young players humble.
Tiller was one of two freshmen on the team during Anderson's first season at Missouri in 2006-2007. The other freshman, Keon Lawrence, rode a bike. That left Tiller as the only Tiger without a method of transportation.
Then one day, Tiller came to practice bragging to the whole team about his brand new wheels. "I'm rollin' now," Tiller boasted.
"We thought he had a bike," senior DeMarre Carroll says.
After practice that day, players were driving down the steep hill on Champions Drive behind Mizzou Arena on their way to get something to eat when Tiller came up behind them.
He had new wheels. Eight of them. On roller blades.
"Everybody has a bike. Not many people were skating," Tiller said. "I tried to distinguish myself."
As he flew down the hill, Tiller lifted his toe to lean back on the roller blades' brakes, trying to slow down.
"Here is this big time D-I basketball player on roller blades," Carroll said. "We were just dying laughing."
What happened next is somewhat open to interpretation.
According to Carroll, Tiller lost his balance and ended up skating on one foot, barely avoiding a wreck. Tiller claims he was simply showing off his moves.
There is also some debate about what Tiller was wearing. Carroll says Tiller wore protective knee pads over his pants and children's bike helmet on his head. Tough-guy Tiller denies wearing pads.
"They say I was wearing knee pads. I wasn't wearing knee pads," Tiller said. "I was skating pretty cool, if I do say so myself."
Tiller was a volatile substance during his first two years on campus. His energy level reached such high levels that, at times, he lost control.
Tiller canceled out his crowd-pleasing dunks and steals with foul trouble, silly turnovers and inaccurate perimeter shots.
Now in his third season, Tiller has learned how to unleash his energy on defense while playing under control on offense. As a freshman, he had six more turnovers than assists. This season, he leads the team with 92 assists, compared to 42 turnovers.
"I didn't become less aggressive, it's just I became smarter," Tiller said.
When he first meets someone, Tiller tries to act quiet. He portrays himself as reserved.
As he becomes comfortable with a person, his goofy, bubbly side slowly becomes apparent.
"He tries to carry himself like very intellectual, and like this great student, which he is," says guard Zaire Taylor, one of Tiller's closest friends. "But he's a clown at times. There's a lot to him."
Simply the mention of Tiller's glasses, a set of black frames with no prescription that consume his entire face, will elicit an immediate laugh from any of his teammates. With them he looks like a cross between a muscle-bound Steve Urkel and Napolean Dynamite.
On a preseason trip to Puerto Rico, Tiller tried to pick up girls at a mall. Tiller, who is in a Spanish class, says he was trying to help teammate Leo Lyons communicate.
The pair failed to interest any of the girls, despite Tiller's Spanish skills which he claims are superb.
"My Spanish is very good, actually," Tiller said. "I might have mispronounced a couple of words and put them in the wrong context, but for the most part I was doing very good."
When his language skills broke down, Tiller resorted to some nonverbal communication. He held his hand in the shape of a phone to his ear and pointed at various things and people around the mall to make his message clear. Tiller's dance of body language might not have helped him communicate, but it did entertain his teammates.
"I like to act a fool off of the court because you have to be silly sometimes," Tiller said.
More than any of his antics, what makes Tiller such a magnetizing character is that smile. No matter what, he's always smiling.
Usually, it's about nothing. No one knows why he's laughing. But Tiller's ability to laugh about everything and anything is endearing.
"He's just a fun person to be around," Taylor said.