Paris Hilton's Toddler Phoenix Walking in Behind-the-Scenes Video

Paris Hilton's kids certainly have their mom's energy ... her son is ready to get out in the world and make a name for himself -- 'cause he's running all over the place! The mother-of-two shared a behind-the-scenes clip from an at-home photo shoot ... and, in it, she reveals she and her husband Carter Reum could barely get Phoenix to keep still -- a recurring problem, she says, since he's able to walk on his own.…