Lawlor was joined by Seth Petruzelli, a friend and fellow fighter who has often been his partner in crime, and strength and conditioning coach Kyle Holland. All three wore adult diapers and nothing else as they cavorted in the Octagon, complete with a fake biting incident.
The three even brought a salt shaker into the cage set up at a local nightclub, so they could throw it over their shoulder as the real sumo fighters do before combat.
Lawlor says the idea was all Petruzelli's.
"Yeah, 100 per cent," he said. "Especially if there are any people who are Japanese and offended by it, 100 per cent it was his idea. Otherwise if you enjoyed it, you can direct all those comments to me."
Lawlor (8-4 with one no contest) fights Francis Carmont, a Montreal-based Frenchman, on Saturday night.
The American has fought three Canadians in his last four outings, defeating Jason (The Athlete) MacDonald and Patrick (The Predator) Cote while losing to Joe (El Dirte) Doerksen.
Lawlor says he has nothing against Canadians.
"I love the Canadian fans. I love Canadian bacon, I love it all. I love Tim Hortons more than anything."
Petruzelli and Holland came to the workout wearing their hotel robes. The salt shaker came from a local restaurant.
"We sat for a while and thought everyone does the same thing, everyone hits mitts, does the pads," said Petruzelli. "What can we do to mix it up and make something different? So I had the idea well sumos kind of do the same thing, just in diapers — and it would be easy to get adult diapers.
"It was an easy costume to put together and we thought it would be entertaining."
Lawlor has long been the Mr. Dressup of mixed martial arts.
He loves to make a grand entrance and has walked out to the cage dressed as Hulk Hogan or MMA icon Dan (The Beast) Severn, not to mention dancing to "Who Let the Dogs Out" while walking Petruzelli on a leash to the cage.
He once did an interview while having a colonic.
"If somebody doesn't like it, really they don't have to watch it. No one was forced to go ahead and watch me get a colonic," he said at the time.
"You know I'm pretty much shameless in some ways. I just see nothing wrong with it."
After growing up in Swansea, Mass., Lawlor moved to Florida where he went to high school and attended the University of Central Florida.
A huge pro wrestling and UFC devotee, he tried his hand at wrestling in high school and went on to win three collegiate national titles as a heavyweight in the National Collegiate Wrestling Association.
He spent some two years on the Florida pro independent wrestling scene, where he competed under his own name. He even took part in an evaluation on the WWE development circuit.
Lawlor kept training MMA during his wrestling stint and had his first pro fight in 2007. He went 4-1 with one no contest before joining the cast for Season 8 of "The Ultimate Fighter."
His MMA nickname initially was Tom (The Filthy Mauler) Lawlor. It started when an old training partner said he looked like boxer Jack Dempsey, known as the The Manassa Mauler.
The nickname has just been cut to Filthy these days.