A source says Lachey, 32, and Minnillo, 25, were doing an R-rated bump-and-grind. "I saw tongues on skin," says the source.
The next night, the pair dined with friends at Fiamma in SoHo then went on to hotel 60 Thompson, where they stayed until nearly 1:30 a.m. when they seen hopping into a cab with several pals.
The couple got close when Minnillo recently shot a part in Lachey's upcoming video.
Meanwhile, Cavallari can’t even get club love: She’s been rejected by her fave L.A. spots lately as cops crack down on underage revelers.