LAS VEGAS — "It's that time! It's time to get naughty," Robin Thicke teased the crowd in between crotch grabs. "We are in Vegas, you know."

Just because the VMA Fandemonium concert was benefiting HIV/AIDS awareness group Lifebeat didn't mean it couldn't also be steamy. Indeed, Thicke and Adam Levine were playing a high-stakes sex-appeal game on Saturday night, trying to outdo each other in a bid to win over the ladies in the audience. When it was time to follow up Thicke's act, Levine told the crowd, "I was like, 'Sh--, I gotta bring it.' So thank you, Robin Thicke, thank you for stepping on my game."

[article id="1569069"](Check out pics of Robin Thicke, Nelly, Britney, Ciara and others stunting in Vegas.)[/article]

Thicke's take throughout his hour-long set was more sultry sweet — alternating between hiding behind the piano for falsetto love ballads and stepping out in front, using his whole body to express urgings that were more euphemistic in the music alone. Thicke cut Lil Wayne's rap out of "Shooter," and thrusted his hips — and the crowd loved it. "We're going to do a bit of everything tonight," he told them. "Some love, some loss, some lust, some regret, and hopefully we're all going to feel better."

Maroon 5 did, at least — because the first thing Adam Levine did was make sure everyone knew, despite his falsetto singing voice, that he's 100 percent red-blooded male. By comparison, Thicke's antics were subtle. Levine, wearing a vest that bared his muscular arms, played it hard. Instead of stopping between songs to chat, Maroon 5 pummeled through one hit after another, treating each as if it were a showstopper — so that when they were through, despite being the headliner, the band had spent less time onstage than its opening act.

With his legs askew, Levine ripped open his vest to reveal even more skin during "Makes Me Wonder" — leaving less to wonder about — and by "Harder to Breathe," was gesturing for the crowd to give him something back. Turns out all he wanted was a little audience participation, which he got during "The Sun." "Come on!" he urged. "That was good! That was really cool." His job done, he strapped on his guitar and started dancing while the crowd sang for him. The rest of the band got a break too, because by the chorus of "This Love," the crowd was singing a cappella.

It wasn't all a love fest — Maroon 5 made sure the element of danger was still present, with Levine reminding the crowd that "Wake Up Call" was about his fantasies of committing murder. "It's about things that I think most people do, in a sick way, fantasize about," he said, before bringing things back to where he started: "So dudes, you have no excuse [not to get any action] tonight. It's Vegas."

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