John Mayer isn't the ladies' man he once was.

A source says a bumpy year has made the 32-year-old singer change his ways. "He's been lying low. HIs CD wasn't huge, and that Playboy interview took him down a few pegs," says an insider of Mayer's controversial quips to the mag -- in which he spewed racial epithets and called ex Jessica Simpson to "sexual napalm."

Find out more about why Mayer is no longer on the prowl -- plus how he's spending his newfound free time -- in this week's Hot Stuff video, as told by Senior Editor Ian Drew and special guest, Sara Bareilles.

Also in the roundup: Bristol Palin is terrified about performing on Dancing With the Stars, Demi Moore initiated a four-hour dance battle at a nightclub in Chicago, Robert Pattinson goes on a cross-country with the boys and Glee's Matthew Morrison cozies up to his ex-wife in Maui, Hawaii.