Exclusive: John Mayer: Jessica Simpson Was "Crazy" in Bed

John Mayer is kissing and telling -- again.

UsMagazine.com has an exclusive peek at Playboy's March issue, where the singer, 32, dishes on everything from his past relationships with Jessica Simpson and Jennifer Aniston to his dream mate.

He dubs 29-year-old Simpson (whom he dated from 2006 to 2007) "a drug."

"And drugs aren't good for you if you do lots of them," he says, adding, "Yeah, that girl is like crack cocaine to me."

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"Sexually it was crazy. That's all I'll say," he continues. "It was like napalm, sexual napalm. Did you ever say, 'I want to quit my life and just f*****' snort you? If you charged me $10,000 to f*** you, I would start selling all my s*** just to keep f****** you.'"

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He didn't share bedroom details about Aniston, who turns 41 Thursday.

But he denied reports that he penned the tune "Heartbreak Warfare" about her. "That woman would never use heartbreak warfare," he tells Playboy. "That woman was the most communicative, sweetest, kindest person."

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He also denied that Twitter obsession led to their split last year.

"There was a rumor that I'd been dumped because I was tweeting too much," he says. "That wasn't it, but that was a big difference. The brunt of her success came before TMZ and Twitter. I think she's still hoping it goes back to 1998. She saw my involvement in technology as courting distraction. And I always said, 'These are the new rules.'"

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Oh, and how many women has he bedded since their break-up?

"I'm going to say four or five. No more," he tells Playboy. "But even if I said 12, that's a reasonable number. So is 15. Here's the thing: I get less a** now than I did when I was in a local band. Because now I don't like jumping through hoops."

These days, he says he is hesitant to settle down.

"I hate being the heartbreaker. Hate it," he says. "If I date somebody and it doesn't work out, it's another nightmare for me."

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Of course, any interview with Mayer would not be complete without an Us Weekly reference.

Asked about his future, he says, "From now on I’m just going to pretend that people really dig the s*** out of me. I've been trying to prove to people I'm not a douche bag by not dating, by keeping my name out of Us Weekly. That's f***** up, man. I'm not dating. I'm not even f******. So now I'm going to experiment with 'f*** you.' In 2010 my goal is to get more mentions in Us Weekly than ever."

You're off to a good start, John!