"Donald, I want to ask you, because the next time I see you, you could be the president of the United States," the show host prefaced his request. "I just wanted to know if there's something we could do that's just not presidential really, or something that we can do now that we're just both civilians..."
What did Fallon want to do? Mess up the presidential candidate's hair.
"I'll be gentle," Fallon promised.