You belong to the portion of the population that can shrink at will. You're just as durable when shrunken down, but something is a little different in your case. Your body, when shrunk, behaves like clay. This discovery was made when you talked to your girlfriend about your fantasy of being stepped on by women many times larger than yourself - giantesses. At first she was a little weirded out, but still willing to give it a go, but only after you assured her you wouldn't be in any danger. She watched you with amazement as you shrunk down - clearly she had never seen anyone do it before. You shrunk down until you barely reached her ankles standing up, then approached her feet as she sat on the couch in your apartment. Her bare feet were a little dirty from walking around the apartment, her painted toenails were dark, almost black, a colour that she knew you liked seeing on her toes. They curled a little as you got closer and you glanced up at your girlfriend, who watched you with a worried look. You smiled at her and assured her again that you would be fine. She took a deep breath and bit her lip, then lifted one foot towards you. Her soles weren't as pink as usual, due to the layer of dust that clung to them. You took in the sight as you stood frozen and let her toes hover over your head. Again she asked if you're sure. You gave an excited yes, then looked up between her toes as they came down. Though she carefully lowered her foot, for you it still felt like several whales came down upon you as you were forced to your knees. In that moment you noticed something was off. Your knees sunk into the ground a little. You looked down in panic, then confusion took over as you saw your knees spreading out like clay. You looked back up to your girlfriend, unsure if you should tell her to stop. Her foot kept descending, pushing your further into the ground, as your legs melted beneath you, followed by your torso. You began to panic again and called out, telling her to stop. The sudden yell startled her, and she did the last thing she wanted to do in that moment. The sensation was strange, your head oozing out from between her toes as her foot had slammed into the ground. Her eyes wide she spread her toes and lifted her foot, covered her mouth with both hands. With utter horror she looked down at you, her shrunken boyfriend, turned into a skin coloured lump of clay with her footprint stamped into it.

The experience left you both unsettled. Your body recovered shortly after and you grew to your normal size, apologizing and comforting your girlfriend who was still very much freaked out. Weeks passed since then, and while she continued to let you lick her feet and shoes, trampled you and used you as her footstool, she flat out refused to act out your giantess fantasy.

Today you devised a plan. She had gone out with friends in the morning and wouldn't be back until evening. You knew in the evening she would be tired. She wouldn't pay as much attention as she usually does. You were going to shrink yourself again and lay down right at your apartment door. Your hope was that she would be too tired to notice you and step on you without realizing it. The thought of being her doormat was enticing. Even if she squished you just a little before noticing, even if she would get mad at you then, in your mind that would be worth it.

As the afternoon waned you decided to get into position, unsure of when exactly she would be back. Even that excited you a little bit, as you lay at the door, like a doormat, waiting to be used as one. Surprisingly, you didn't have to wait long. The keys were being inserted and turned, and as your girlfriend pushed the door open, you noticed she was talking to someone behind her. Several voices reached your ears. As the door opened you saw your girlfriend, and several of her girl friends, all dressed for the summer weather, wearing sandals like your girlfriend or flip flops. And while the prospect of being used as a doormat by all of them excited you considerably, you knew your girlfriend would be livid if you actually did it, so you decided to quickly get up and hide. Except you didn't get the chance. When you looked up, ready to sit up, the sole of your girlfriend's sandal was already close enough you could make out the thin ridges of the tread on her heel. Indeed you became quite familiar with the tread as it came down on your face, flattening it beneath her weight, and leaving behind a nearly perfect print of it. Your girlfriend had noticed you, but not in time. Looking back at you she tried not to let her panic show. She was torn between desperately wanting to avoid her friends realizing what you were doing there, and not wanting you to be turned into a human doormat. Her first friend sealed your fate, stepping on your abdomen with one sandalled foot, then on your chest with her other, flattening you, squeezing out your body clay underneath her soles as she commented on the loveliness of your apartment. When she stepped off you saw her next friend cast a curious glance over you before her flip flop filled your vision and you felt your footprint stamped head being flattened beneath her larger shoe sole. She also said something, but you struggled to understand what, as she had decided to stand on you and crush your legs under her other foot. Eventually she did step off of you, though she didn't move far. With your head flattened you were forced to stare upwards so couldn't quite tell what she was doing, but the way she moved her legs and looked at her feet, it seemed she was taking her flip flops off. You were proven right when she pulled her left foot out of her flip flop and set it down, now crushing your face beneath her bare sole. The pressure wasn't as even as the flip flop so you were able to make out her words this time. She was commenting on how interesting the doormat felt, and you felt your clay face being ground beneath the ball of her foot while her toes dug into you, feeling you beneath and between them. Your girlfriend watched with mixed emotions, both worried and infuriated by what was happening to you beneath the foot of her friend. She decided not to respond to her friend's observation and instead asked her to check out the couch in the living room. Shortly after the foot lifted from your face, with parts of your clay skin stretching before dislodging from between her toes. Your girlfriend was appalled by the state of your face, though she took care not to let it show on her face. She smiled at her last friend, the only one in her group who was so self-conscious of her feet that she decided to wear a pair of Converse, both of which came down on your body, and stamped the iconic tread profile into your face and chest. Curious about what the prior friend had pointed out, she looked down at the strange almost skin coloured flap of clay beneath her feet, lifted one foot and giggled at the perfect footprint her shoes had left on you. She then promptly decided to add more, stepping on you over and over, covering your entire length - which increased as you were trampled flat - in her footprints. She chuckled and offered your girlfriend a half-serious apology before stepping on your head and leaning down to untie her shoe. She took them both off on top of you, then moved them aside while she flattened you beneath her sweaty black socks. Your clay skin got along with her socks so well you got stuck to them and experienced - if only for one step - what being a human shoe was like, before the furious toe wiggling and being dragged along the floor dislodged you. The girl apologized to your girlfriend again, this time somewhat more sincerely, before heading into the living room. Flattened and tossed around you lay before your girlfriend who glared daggers at you. She crouched and picked you up, turned you so you faced her. Then, in an agitated whisper, she explained that she had intended to introduce you to her friends today, but that you had ruined that chance for the day. She continued informing you that - since you had "introduced" yourself as the doormat - you would have to keep up the act until they left. And that very much included submitting to their feet when they left.