One of the things Sansa has always liked about Lord Petyr Baelish is that he knows what he wants. She has never quite had the conviction, the confidence, the pride to be able to say so definitively what her goals are. She's not someone who makes decisions. She's not a leader. He is. A quiet one, maybe- and most men don't know they're following him when they are- but a leader, without question. Sansa doesn't think she knows herself well enough to be so sure. She, for instance, does not quite know what she wants with Lord Baelish himself.
She likes him. She thinks. It excites her to be near him, and she feels very electric when he is. Watching him at court is exhilarating, and hearing him masterfully weave the tales and speeches that move great men to action is fascinating, even when she can tell he's not working for any noble cause. And yet, it's frightening. Someone with such power feels deadly to be near. She has little control over herself, and could very well be just another of his victims. Her mind races in his presence, trying both to please him and detect the webs he weaves. She knows she likely fails at both and spends hours turning over her mistakes after they part, determined to be more clever next time. It causes a stress on her which is both taxing and addictive.
She finds herself anxiously preparing for him every time she is to see him. Bathes, grooms, rehearses. She fusses with her dress, pulls it down in front, to expose the faintest hint of bosom, just for him. Part of her feels intimidated by him, and so must earn his respect by being desirable, attractive, equally important- in her own way. Another part… just wants him to see her. It is a game of sorts, vying for his attention, making herself the shiniest jewel she can be so as to catch his eye. She's not sure what she aims to do with it once she's caught it… but when she does, when he turns his iron-grey intent on her and locks on, it's as if he's pulling her heart straight out of her. Everything stops. She feels all at once foolish and brilliant, too young and too old, beautiful and homely.
She knows that he cares a great deal for her. He goes out of his way to help her, even risks his wealth and safety for her. But at the root of his affection, she knows, is her mother. He sees her only as a daughter he should have had, and his feelings for her are that of a caregiver. Yet, occasionally, he flashes her a smile that must be just between them- just hers. It gives her a shiver she doesn't mind, and she could swear there's something else behind it. When he gets very close and she smells the sweet spicy musk of him, mingled with the mint he chews when he leans in to whisper, her feelings toward him are not so straightforward. There is a rush, a tightness, a warmth in the back of her stomach, down her spine… the muscles between her legs flex and something pleasurable flickers deep inside her. When she feels his fingers on the small of her back, when his lips caress the back of her hand, when his breath hits her cheek… her own breath catches, and she freezes. She would hate for him to know, it's shameful and inappropriate. He's far too old for her. But she doesn't seem to be able to stop that feeling. Doesn't really want to.
To be sure, Sansa has no established fantasy about him. She does not envision any particular act or future. She's not even sure, given the reality of an advance from him, she would or could do anything about it. Lord Baelish is more a concept, a feeling, a ghost to her than a real person. She has impulses, but no idea how to fulfill them or whether she'd want to if she did. The vague, dull ache of want that takes her when he is near is enough to sustain her, to keep her looking for him in a crowd and waiting for his unannounced visits to her chamber.