It began as it always did, deep in the pit of her stomach. At first it was just a twitch like a strained muscle. It would be there for a second and then gone, only to return some minutes later. The twitch would gradually move forward and down until it was visible on the surface as her abdominal muscles clenched in a steadily hastening rhythm. She knew it was coming the moment it started early that morning. It would take a few hours, but the process was unstoppable and the outcome inevitable by now. She planned accordingly.
By four in the afternoon, Amu was walking unsteadily, as if mildly inebriated. The clenching was getting worse. By now, the twitch had become a spasm that lunged deep into her belly every time, at a point just above the apex of her thighs. It would come every two minutes and last for anywhere up to ten seconds, like a hand reaching in and squeezing her insides. Her panties were sopping through, a trickle of moisture dribbling down her naked inner thighs and soaking the tops of her knee-high socks. Nobody seemed to notice.
At four thirty, Amu was in a department store and running right on schedule. The bag full of new clothing bounced at her side. Two decent outfits, several sets of fresh underwear and some comfortably sexy lingerie. A treat, she told herself. She left the cashier and strolled casually back past accessories, through the perfume counters towards the door. They would be watching. Fooling the cameras was always the difficult bit. Everything else was easy.
Another convulsion stabbed at her abdomen, this time powerful enough to make her knees buckle. She paused to lean up against one of the perfume counters, waiting for it to pass, trying not to show it on her face. Her cunt was a swampy mess now in the flimsy cotton panties, running in long rivulets down her thighs. Hopefully the pleated skirt would keep unwanted eyes from noticing.