During a Thursday taping of NBC's "The Tonight Show," host Jimmy Fallon had an important question for Donald Trump … Could he mess with his hair?

While Trump looked apprehensive, Fallon promised: "I'll be gentle."

The GOP candidate finally agreed, awarding Fallon a rare opportunity, while adding that he hoped voters in New Hampshire, his next stop, wouldn't mind.

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That's when Fallon went where few have gone before, putting his fingers through Trump's famous yellow hair. He gave it a good shake, as the strands of hair toppled over.

We won't lie, it looked a little scary. But he gets points for being a good sport. Trump then tried to fix his famous hairstyle, with little success.

To make him feel better, Fallon then rattled his own fabulous mane.

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Last year Fallon got to practice this move on … wait for it — Hillary Clinton.

After Clinton asked him if he'd ever touched Trump's hair during an appearance on "The Late Show," she offered Fallon to give her own hair a go.

"You wanna touch mine?" she asked. Fallon tugged her hair and declared, "It's real!"

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Check out Fallon's adventure through Trump's hair in the video below.

"The Tonight Show" airs at 10:35 p.m. on NBC.