NBC NEWS- Chrome bumpers, shiny wheels & custom paint: many car and truck owners like to accessorize their vehicles! But there is a new truck accessory dangling from trailer hitches in some states that’s causing some to go nuts.

They’re called "Truck Nuts" and they have become the hottest vehicle accessory.

Whether plastic or steel, color or chrome, these babies have become a million dollar business.

One store owner said, “They are going nuts over these things. Once or twice a day people ask for them. Dangling do-dads. Dangling do-dads!"

Kati Trimmell has a pair of pink do-dads dangling from her Dodge truck.

The 20-year-old cowgirl, who got her nuts as a Christmas gift, works at a local western wear store.

She said "steel, colored or chromed, truck nuts sell almost as fast as wranglers & ropers."

“You'd be surprised at how many women buy them,” said Trimmell. “The pink ones are my favorite because I love pink.”

They're an eye catching novelty draped off trailer hitches across Oklahoma. But not everyone shares Kati’s enthusiasm for "Truck Nuts".

Oklahoma State Representative Joe Dorman is a moral compass at the Oklahoma State Capitol.

He's authored a bill this session to ban explicit videos from car TV screens. And he finds truck testicles equally vulgar and offensive.

“You shouldn't have to explain to your kids at a very young age what is on the vehicle. It's ridiculous to have something like that. Kids deserve the birds and bees speech at the right time not because of something someone else is doing down the road,” said Representative Dorman.

Other states have already introduced legislation to remove these things from trucks and SUVs.

“If someone introduced a bill to ban these things, I would not be surprised if it passes and lands on the Governor's desk,” said Dorman.

But some believe regulating truck and SUV accessories of any kind infringes on free speech.

“You've got stickers of naked women on windows but you can't have something like that? It makes no sense to me,” said Trimmell.

Funny or offensive, it's all in the eye of the "bull-holder."