Meanwhile, Nate is about to tell Blair something very important that is going to ruin his relationship with Blair, his relationship with Serena, and their relationship with each other. I don't know why he's going to do this, or what purpose he thinks it will serve, but I do think he's doing an impressive job of trying to bring his entire world down around his ears, which he's been threatening to do in every scene so far. Meanwhile, she's looking totally hot and candlelit and gets right up on his jock. He squeezes out an emotion and starts spilling about the mysterious thing.
Chuck tells Alfonso in the kitchen that he is a stud, then sends him home. Chuck is wearing a lavender jacket over a purple and a yellow Polo, and a pink pocket square. He looks like a rapper's valet. Serena enjoys her sandwich, and Chuck says that she can thank him with some sex. She laughs at him and arches an eyebrow: "It's a...sandwich, Chuck." Chuck is not dissuaded, because he is a perv and rapist. Serena, gunless, holds her own for a while, and then Chuck presses his advantage by flashbacking to the Shepherd wedding, last year, right before Serena left town.
Shepherd wedding, last year, right before Serena left town: Serena's dancing around on the bar, Nate's trying to get a stolen bottle of champagne open, they're both blitzed. They fight over the bottle for awhile, and then it goes off prematurely, and they laugh drunkenly about this, and then they're covered in champagne, and then they start making out. You kind of see what Bad Girl Serena's like, and it's fairly awesome.
Blair, who's getting the flashback from Nate at the same time, is like, "But that was it, you guys kissed." Obviously not true. She starts crying.
In the flashback they go totally nuts doing it. Chuck stands on a balcony looking super-gross and thinking about masturbating.
Chuck says the most important thing of the episode, which is that this -- best friend and the boyfriend -- means that Serena's more like Chuck, which is to say quite bad, than she'd like to admit. He calls her S, by the way, when he says this. Serena protests that she is trying to change, and he responds that not only was she cooler back when she was evil and slutty, but that the rape is still in progress. She tries to fight him off.