The first time the sounds make it through her bathroom's thin walls Melissa isn't quite sure what she's hearing.
She knew it was moaning of course. Breathy gasping moans that made her own legs clamp instinctively even as she turned off the running water of her shower to hone in on the sound. She knew those sounds, familiarity calling forth arousal as the panting grew sharper and closer together on the other side of the wall. But there was still a layer of confusion she couldn't quite shed.
Her bathroom wall was against her neighbors.
Harriet Bell was as prim and proper as they came. An accountant who wore matronly long skirts and wouldn't be caught dead in a top that couldn't be buttoned up all the way. She pulled her ponytails back with military precision, and there was no conceivable way that was the woman masturbating on the other side of their shared shower wall.
Except the only other option was that she had a very forward guest making those sounds, and letting Harriet know. The microscopic apartments on her floor had the same square footage and terrible sound insulation. If Harriet had a guest making those sounds she'd be able to hear it just as well as Melissa could, if not better. Surely Harriet would have interrupted at the first opportunity. Or maybe Harriet was aroused too.
Melissa decided she liked that though. Hands absently cupping her breasts. She liked the thought of prim and proper Harriet, flushed and scandalized. Biting her full lips as she squirmed in her bed. She was naked in the day dream, skin flushed and hazel eyes wide with shock and arousal. Surely the woman in the shower was a lover. One Harriet would be tempted to join. Melissa slid a finger down her wet folds, a breathy groan of her own escaping her as the fantasy ran through her mind's eye. The mystery lover in the shower mirrored Melissa's own physique without conscious thought. A thicker woman that could pull the slimmer Harriet close, hard nipples rubbing against each other, shower slick as they used the pretense of showering to run their hands all over each other's bodies.
Melissa's mouth watered as she thought about brushing her lips against Harriets hard peaks as she sucked on her nipples and gripped the magnificent ass that no skirt had been loose or long enough to hide. Her finger rubbed faster against her clit as she slipped them inside Harriet in the fantasy. The heated slick walls gripped her fingers as she hooked them in search for the slightest hint of texture, for the spot to assault tenderly and drive Harriet insane with lust.