A little background:

Jim and Amy had been dating for a year. Their relationship had started seeming to grow cold after the first ten months or so, and Jim had no idea why. At first the two of them made love several times a week, then it was only even two or three days. But for the last couple of months it had only been once or twice a month. Mostly when he came over now they just watched tv. He was starting to suspect that she was seeing someone else. But how could he prove it. Being a science teacher at the local high school, who’s specialty was chemistry. He began working after school hours, in an attempt to find a way to see what was going on.

Testing the formula:

Finally after months of trying he thought he had the perfect formula. He was unwilling to test it on himself so, he used one of the three white mice that was in the school laboratory. He gave it one drop of the formula with an eye dropper. The result was almost instant. The mouse disappeared, though you could tell it was still there because it was running on its little exercise wheel. After about an hour the mouse reappeared, perfectly healthy and none the worse for well. He repeated the experiment several times until he was absolutely sure that the formula was safe. Now it was time for human testing.

He chose a girl from the senior class and had even sent a note home with her for her parents to sign. The note however only asked for permission for the girl to help him with a lab project. It didn’t say what the project was or that she would be experimented on.

The next day Jane stayed after school to help him with the project. As she was much bigger than the mouse, he gave her three drops of the formula. Again the result was instant, although she didn’t completely disappear. You could however see through her. He gave her one more drop, then she did completely disappear. She stayed invisible for an hour, and he knew he had found the formula he needed.

Jane saw the results of the formula for herself when she looked into the mirror. She loved the knowledge that she was invisible. There was however one slight problem. Though the formula made her invisible, it didn’t make her clothes disappear. When she looked into the mirror she could see her clothes but not herself. It looked as if her clothes were suspended in midair but with her natural body shape including her shapely B-cup breast and nicely rounded hips.

With Jim looking straight at her, she did something she never would have done had she been visible. She removed her clothes right down to and including her lacy panties. Then totally invisible she snuck around her teacher and rubbed his shoulders and back.

He enjoyed the feel of her hands on him. He had an invisible eighteen year old girl caressing him. Though he couldn’t see her, he knew she had come around in front of him when she began to undo the buttons of his shirt and remove it. In the back of his mind he knew she would not have done this had she been visible. She had already removed his pants and was about to do the same with his underwear, when the formula wore off. Suddenly she was visible again. Over come by sudden embarrassment at being naked with her teacher she covered herself as best as she could and ran back to where her clothing was. Hurriedly she put her clothes back on, and he did the same.

They talked for seemingly hours about how it felt to be invisible. She confessed that it made her feel free to do whatever she wanted, and that she had secretly had a crush on him since she was a freshman. He assured her that it was perfectly alright that she had had a crush on him. He even admitted sheepishly that he’d had a bit of one for her as well. He asked her not to tell anyone about the formula and she agrees, as long as she could take some more of it later. He agreed. He also told her that he wasn’t feeling well and that he would probably take a sick day tomorrow and she didn’t need to stay after school, but he would definitely see her after school on Friday, which was the day after.

A little revenge:

The next morning he called in sick. He went to the office where Amy worked. Instead of going directly into the room he knew she would be in, he stopped at the restroom near it. He used four drops of the formula to become invisible and stripped. Storing his clothes where they would be safe. He went into the room where Amy worked. He had only been invisible and in the room with her for about fifteen minutes, when it happened. She went into her bosses room. Quickly and silently he followed her, getting into the room before she had closed the door. Her boss was laying naked on a couch. She quickly stripped and straddled his six inch cock. She began to hump up and down on it. It wasn’t until she leaned forward to rub her tits on her bosses chest, that the idea hit him. Quickly not letting any sound give him away. He got behind her and without any warning forced his almost seven inch cock into her ass. She screamed at the invasion and pain of having her ass penetrated. Not feeling his added weight, her simply assumed that she was having an orgasm, despite the pained look on her face. He continued to fuck her ass until he shot his load into her.

Amy was enjoying riding her bosses cock she leaned forward to get the additional stimulation of rubbing her nipples on his chest. She had only felt that stimulation for a few seconds when the impossible happened. Despite the fact that she couldn’t see anyone or anything, she felt something long and hard pushing its way up her ass. She had never allowed anyone to fuck her there. She had never even touched herself there except to wipe her butt when she pooped. Now something was pushing its way into it. The pain was incredible and she screamed. Obviously her boss was loving it because he seemed to begin pumping harder and faster. She felt both of her holes being filled at the same time and screamed out again, this time in a mixture over pain and pleasure. She didn’t know what this invisible thing was in her ass, but in combination with the cock in her pussy it had felt good at the end.

Unseen by anyone Jim left to go back to his clothes. He got dressed and left. He did make sure that he was once again visible when he left. Since no one at her work had ever seen him before no one could know that he had ever been there. He broke up with her that very night, by phone so that she couldn’t by any reflection on his face know that he had been the one to take her anal virginity.

At school the next day:

He decided that he liked his newfound freedom. He knew approximately when all of his students had their respective gym classes. Fortunately, for him anyway, his free period coincided with the freshman girls gym class. He decided to take a little of his formula and visit that class. Though he was careful not to let his presence be known, he enjoyed watching the girls take their showers. Seeing the girls rub soap onto their tits and pussies was thrilling.

At the end of the day when Jane joined him, he asked her if she still wanted to take some more of the formula. She said that she did, so he gave her four drops of it and she disappeared again. Unlike the last time she immediately stripped him. He felt her take his cock into her mouth and begin giving him a blowjob. He found out that there is nothing like getting a blowjob front an invisible girl. It was incredible, in only a few seconds he was laying on his back. He was on the verge of shooting his load, when she suddenly stopped. He was about to ask her for more, when he felt her sliding his cock into her wet channel. His cock was an inch or two into her when he felt a resistance. Then she rose up and slammed herself down, pushing half of his hard cock into her. It was then that he realized she had been a virgin.

Jane was loving the fact that she was invisible. She could and did undress him. She wanted to see what a man looked like naked, she had never seen one before. She had gotten close when she had started undressing him the other day, but she was only down to his underwear when she had become visible again. She didn’t want him to see how embarrassed she was and had ran to her clothes and gotten dressed. She was determined that today would be different. Today she was going to find out what it was like to actually have a man.

As soon as she had his clothes off, she licked and sucked his cock, though like a much younger girl she thought of it as a dick. She felt it harden more and more as she bobbed her head up and down. She knew she must have been doing something right when his knees seemed to weaken and he went to the floor.

She felt a strange tingling in her crotch and suddenly knew what she really wanted to do. She removed her mouth from his cock and straddled his waist. Taking his cock into her unseen hand, she guided it to her sexual opening. Gently at first, she eased the tip of it into her opening. She loved the feeling she felt, as it slowly stretched her virgin sex. She had only gone down a few inches when she felt a pain. She had heard other girls talk about feeling a little bit of pain the first time they’d had sex, so she wasn’t too worried. She also remembered that the girls who had said that, when they’d lost theirs it had been with a quick thrust and had little pain, while others whose boyfriends had slowly pushed in had seemed to have a lot more pain. So she rose up until his shaft was barely in and slammed herself down on it. She gasped at the slight pain as he shaft broke through her hymen and had to hold still for a few seconds as the pain dissipated. Once there was only that good, well stretched feeling, she continued to sink down on the hard rod filling her. She knew she had done it when she felt his thighs touch her bare add cheeks. After only a second or two, she began to ride his cock in long slow strokes. She gradually quickened her pace as she grew accustomed to his length and girth. Somehow, despite his inability to see her, he reached up and began to stroke her tits and nipples.