You had wondered if being a bra would be too passive, and to be sure, you're not in control of your motion, but that doesn't mean that you are a passive spectator. Bras serve a purpose, and while this girl is at best a high A cup, you are too, and with each step she takes, the soft-yet-firm orbs you hold strain against you, while you hold them in place, a dance you were literally designed for. But it's so much more than that. All your senses spread through the bra -- you can pinpoint them if you want, look from a spot in the bra, but if you don't, the sense gets smeared around it. And that means that you can smell and taste and feel this young girl, the dry sweat on her young flesh, the delightful nubbins of her nipples. You are more aroused than you ever thought possible, and you've been incredibly aroused.
The outside world is distant to you; this girl is everything. You do catch snippets here and there -- she has homework, maybe get together later -- but you pay it little heed. You simply ride with the girl as she rides a bus, then hops off and heads home. Each step is rapturous, each breath delicious.
And then, and then, just when you thought you had reached your apex, she goes up to her room to read for class, as she always does, laying face down on her bed. Not that you know she always does this. You discover it as the world tilts and the girl's breasts push hard up against you, pinning you against the fabric of her dress, which is pinned against the bed.
She lays like that for over an hour, reading and texting and so forth. Then she gets up, and goes about the nightly routine. You sense that there is dinner being eaten and conversations with family; you hear a mother, a father, and a sister -- older sister, maybe? You're not sure, and you're finding it very hard to pay attention. Even when your owner speaks, and her voice rumbles through you, it feels more like a force of nature than conversation.
It is the greatest seven hours of your life, but alas, all good things must come to an end. Your owner finally strips the dress that had covered you off, and you see her looking in the mirror briefly. She's in a bathroom, and there's water running in the shower.
She's a very pretty young thing, and you are disappointed as she slips her hands behind her and unclasps you, dumping you atop the dress on the floor. You feel a bit cold, and sad, but you do at least get one final great view of the girl sliding her panties off, and dropping them on top of you. She then steps into the shower to clean up before bed.
There is part of you that feels very much like sitting still. You realize, distantly, that by merging with the bra, you have taken on the bra as part of yourself, and that part calls to you like a siren, telling you to wait with it, just a wash and a few days of waiting, and she'll wear you again, you can wait....
Then again, you can taste and smell the panties above you. And that gives you an idea. True, those panties are used, but if you're quick, there should be a fresh pair on the counter. You've been a bra; why not try her other underwear?
But the call of staying a bra is strong enough that you think maybe you should decouple, and become animate again. No, not a full-sized guy, that would creep the girl out. But if you transformed into an inch-tall person, you could explore the house, get the lay of the land.
Much to think about, but little time, the girl won't shower forever.