She's wanted him for so long that she can't seem to say no, even when she knows that she should. Even when Faye knows that this isn't about her at all. Ever since Cassie Blake waltzed into town, everything seems to be about the perfect little blonde witch. Even those things that really shouldn't have anything to do with Cassie. Take for instance, Adam and Jake. Adam should always belong to Diana and Jake should always be hers. But Cassie somehow cast a spell over the two boys and now they're both obsessed with Cassie.
Still Faye greedily takes whatever it is Jake is willing to offer her. Even if she's just a substitute for Cassie. When he pulls back to take off his shirt, Faye doesn't allow herself to fall for the illusion. Jake wants her but this is about Cassie and her inability to decide if she wants Jake or Adam. Faye pushes Cassie out of her mind and focuses on the moment. It won't last so Faye wants to enjoy every second of it while she can.
Tomorrow she'll lose herself in recriminations and she'll curse Cassie. Tonight, she's going to pretend that Cassie never came to town, that Jake is still hers.