She once underwent a colonoscopy on live TV, but Katie Couric seemed even more exposed during her May 12 hosting stint on The Tonight Show. During the monologue, "I never felt so alone," Couric told PEOPLE. "But it turned out to be just the right mix of adrenaline and terror."

Indeed, Couric enjoyed sitting at Jay Leno's desk. Clad in a revealing black Marc Bouwer dress and 4-in. pumps, she gamely joked about Colin Farrell, her Today cohosts and her breasts—"They're real!"—though during rehearsals she nixed jokes about poop ("Gross!"), masturbation ("Um, I don't think so") and Scott Peterson ("Definitely not"). Earlier, on Today, Leno chatted up Secretary of State Colin Powell and adjusted to sharing the spotlight. "It's weird, picking up all these cues," Leno says. "Am I up next? Do I speak after he does?"

While the stunt paid off in the ratings for both shows, "I think they should both keep their day jobs," says New York Post TV critic Adam Buckman. That's fine by Couric, who had only one plan after wrapping Tonight: "I'm going to go get drunk with my friends."