Ed Westwick lowers his head, narrows his eyes and curls his mouth into his signature Chuck Bass snarl. Hovering at the edge of the “Gossip Girl” schoolyard set wearing one of the dandy’s trademark candy-colored garments (this one’s a traffic-cone orange trench coat), Westwick hops up and down, shaking out his arms like a boxer.

His foes? Two of TV’s most, well, gossiped-about girls, Serena van der Woodsen (Blake Lively) and Blair Waldorf (Leighton Meester), the lead characters on the modestly rated but wildly buzzed- and blogged-about CW teen drama that’s arguably permeating pop culture in a way not seen since “The OC.”

On Monday (7 p.m.), Serena, Blake, Chuck and the rest of the preternaturally groomed gang of private high schoolers are back on the Upper East Side to continue the cavorting begun before the writers’ strike. Shenanigans then included breaking into the school pool for a martinis-and-bikinis party; sleeping with a boyfriend — and his best friend — as Blair did; and taking the inevitable pregnancy test. All of which, of course, “everyone does,” jokes Meester, especially within the same week.

Expect ratcheted-up raciness in the final five episodes of Season 1, cast members say. “These scripts have been really, really juicy and exciting,” Lively, 20, says.