Apropos of nothing, Blair strides up and starts screaming about "Enough with the blackmail!" and chasing away the young lady he was currently seducing. Slow as slow, Chuck takes off his sunglasses and looks at her like she's a crazy person, which is what she both is and is acting like. Her point is that she's doing her best to ignore Nate until Chuck calls off the attack -- which, as it would for B herself if she didn't have a hockey stick or implement of death handy, amounts to lying in wait, leering, and generally letting her drive herself crazy. He gives us the backstory that in fact the "avoiding" she's been doing is part of the blackmail: "I didn't say forever, just until the sight of the two of you together doesn't turn my stomach." She asks when that will be, and the entire viewing audience is like, "Never!" (Beat.) "Unless Nate gets naked again!"
Chuck encourages B to practice "patience and restraint," lest he come down on her like a sack of rapists, and she begs him to torture somebody else. He'll find somebody, but until that point -- about five seconds, I'm guessing -- she's the lucky winner of The Chuck Is Shadowing My Every Move Creepily Sweepstakes. I'd be creeped out, I guess, but the fact is that he's playing the Blair game really well, whether or not he's in love with her. She's a power player just like him, and vicious just like him, and he's probably playing this nicer than she would. Actually, she was way worse. Blackmail was like Day One back when it was Serena on whom she was constantly going apeshit: she hurt him, so she has to be broken, and once she says uncle, they can reevaluate. Given sufficient money, time and energy for drama, and no legal recourse, and we're all playing by Blair's rules anyway: he's admitting she's the one in control by playing this weak card, because it's the only card he has, and every shitty thing he does in this episode just exposes that weakness more and more. This kind of behavior would be totally gross if she was a delicate flower, or he had the upper hand, but in fact she is Blair: she's more man than he could ever be, and she's holding all the cards, so it's all actually like totally feminist. You say in the Metro Fourth Wave all the boys are turning into girls? No way, man. All the girls are turning into boys. And that is fantastic.