Your mom starts chanting: "For my son, the worst deadweight / May he have a fitting fate / To carry me, through day and night / Strapped 'cross my heart, and quite the sight!"
"What...?" you begin, but are cut off when, at her chant's conclusion, you burst into a puff of smoke. This is literally what happens, and to try and describe the sensation of it--your physical form dispersing, detonating outward and becoming immaterial vapor--would be to attempt the impossible.
The smoke clears, and after a very confusing few seconds where you are fully non-corporeal, your particles reconstitute themselves, depositing you at the foot of the couch where you were reclined, and where currently the bowl of chips that was sitting on your lap has been overturned, spilling Doritos everywhere. You cannot move. You're twisted at an inhuman angle, with your "arms" (what feels like your arms) pulled behind your "back" (what feels like your back), and your "back," which is also your "torso," which is also your "face," resembling a double helix, with one half flipped backwards and staring at the carpet, and the other half crumpled and facing the ceiling. You are also really, really tiny, and completely without "legs" (or anything that feels like legs). The closest you can get to describing it is comparing yourself to a head in a jar, like the ones you see on Futurama, but even that isn't quite getting at the truth.
Your mom interrupts your inner monologue by walking over and picking you up between the thumb and index finger of her right hand. "Aww," she says, "you look so cute!! I can't believe I didn't change you into this earlier!"
You would use this opportunity to inquire how exactly your mom has changed you, and why she is able to pick you up with just two fingers like you weigh barely more than a feather, and what about you, precisely, does she find cute, but you are unable to talk, lacking any aperture resembling a mouth. All you can do is think these thoughts, and imagine that your mom can hear them somehow, while she carries you out of the living room, down the hall, and into her bedroom, humming all the way snatches of ABBA tunes.
She takes you into the bathroom, going straight for the mirror where she holds you up and stretches you out, gripping you (again, just with thumb and index finger, both hands) by your "arms." "Look at you!" she exclaims. "Aren't you just the cutest little bra that mommy could ask for?"
"Cutest little" bra, you're in no position to affirm (or argue), but there is no denying that you are a bra of some sort. A satin, sheeny bra, to be exact, velvet and wide-cupped, padded to service your mom's double D's. She pulls you up against her chest, letting you feel the way your contours perfectly match each breast, giving you a taste of where you'll be spending most of your time now.
You can't scream, but you do the best mental approximation of it, and despite not having a heart (except for a bow stuck to the middle band, tied into the shape of a heart), you have a vivid recollection of what it would feel like right now if you did have a heart: pounding 200 beats a minute, slamming against your chest, and then bursting from the sheer shock of it.