Cathy is a girl’s school gym teacher. She is twenty-six and lives with her boyfriend Bill.

One day she’s covering an English class of fifteen-year-olds for Mrs Collins, who is sick. The pupils are sitting a test and Cathy is basically just watching them to keep order.

One of the girls, Naomi, raises her hand: she has a question. Cathy goes over to her desk and stands behind her, looking over her shoulder at the test paper. As Naomi explains her problem, Cathy’s eyes stray to the front of her blouse. It’s gaping and Cathy can see right down the front of it. She stares at Naomi’s young breasts, they are lovely, quite small with the tops showing above a white lacy half bra.

Cathy has never considered herself to be bi-sexual. She admits that she will look at a beautiful girl or admire a nice pair of legs, breasts, or bottom, but in a purely appreciative way, while trying not to compare them with her own.

There was actually one occasion several years ago ... Cathy was in a store that had recently opened, and she was looking for some new blouses. She’d selected three possibilities and gone to the changing rooms to try them on.

When there, she discovered it was a communal changing room. She had thought that no one used them anymore, but it was fine. She was trying on the first blouse when a young girl walked in, probably eighteen or nineteen by the look of her. She was carrying a selection of lingerie on hangers. The girl was incredibly slim with small breasts and blond hair down almost to her waist.

Cathy was looking at the first of her own blouses in one of the mirrors, which were on all of the walls of the room. She could see, out of the corner of her eye, the young girl stripping to her underwear; she had her back to Cathy.

Although she was very slender, she was not angular or bony in any way, and Cathy admired her, in what she felt was a purely aesthetic way; she had an incredible coltish beauty. The girl then took off her panties. Cathy saw that she was shaven down there and felt her face flush as she realized she was staring at this girl’s vulva. Actually, it wasn’t just her face that was flushed.

The girl then turned away from Cathy, bent over, and pulled on a disposable thong. When Cathy saw her naked bottom it was delightful: incredibly firm with dimples like a young boy’s. She felt her pussy clench at the sight and looked away quickly, trying to concentrate on her blouses.

The second blouse didn’t look right and the third was too big. The next time she caught sight of the girl, she was changing between bras and Cathy could see her breasts, they were perfect little cones but turned up at the nipples like baby ski slopes, with tiny areolae and hard little nipples.

The tingling in Cathy’s pussy was now joined by a distinct moistness, and she turned away, trying not to stare. She had found herself, without consciously thinking about it, trying the first blouse on again. It was nice but the effect was ruined a bit by the black bra she was wearing, she really should have worn a flesh-colored one. She decided to try the blouse without the bra. She took off the blouse and, as she took off the bra, she felt amazingly aroused, exposing her naked breasts to this beautiful girl. She felt even more aroused when she saw, in the mirror, that the girl was looking avidly at her chest.

Cathy put the blouse on and checked herself in the mirror. The material of the blouse showed off the shape of her tits really nicely, and her erect nipples could be seen clearly. God, she thought, Bill would burst his trousers if she went out looking like this. While she had been thinking this her fingers had been smoothing down the blouse over her breasts and running over her nipples. Her now very hard nipples. She checked and, fuck, the girl had been watching all of this.

Cathy blushed when she realized what she’d done and dressed back into her own clothes hurriedly. She bent down to pick up the blouses and her handbag and, as she started to stand up again, there, right in front of her, mere feet away, was the near-naked bottom of the young girl. She had bent over to pick up a bra from the floor and, as she did so, her ass cheeks parted slightly. Cathy could see the edges of her darling pink asshole peeking from either side of the ribbon of the thong between her cheeks. Cathy’s whole body seemed to flush, in particular her pussy.

She gazed at the vision before her for long seconds before panicking and standing up. As she did so her eyes had met those of the young girl in the mirror. The girl had looked directly at her with the most lascivious smile that Cathy thought she’d ever seen. Cathy tried to change her own expression from what she suspected was a mixture of embarrassment, guilt, and probably lust, to a smile.

She turned and rushed out, gave the blouses to the woman attending the changing room, and went to find her car. It was a shame she’d really liked that pink blouse.

Nothing like that had happened again, but Cathy did start shaving her pussy regularly the next day, much to Bill’s delight.

Cathy has flashbacks to that day in the fitting room while staring down at Naomi’s young breasts. She feels a familiar tingle in her pussy and she can feel her nipples starting to swell.

“Do you think that would be OK, Miss?” asks Naomi, jogging Cathy out of her reverie. She realizes that she hasn’t heard a word that Naomi has said to her.

“Yes, yes I’m sure will be fine,” Cathy replies, hoping that she hasn’t agreed to let her have the rest of the week off, or to let her dance around the quad naked. As she has the latter thought, her brain helpfully supplies images of what that might look like. Cathy feels a strong urge to look down the girl’s blouse again and moves back to her desk hurriedly.

Two days later, Cathy is asked to cover Naomi’s English class again as Mrs Collins is still off. Naomi has moved seats to one at the front and is sitting in the sun that is shining through the window.

Cathy has asked them to read the next three chapters of their currently assigned book, and is sitting at the front of the class reading the same chapters. She looks up from time to time to keep an eye on them and, on one occasion, notices that Naomi has parted her legs slightly. The sun on her short white skirt means that the gap between her legs is well-lit and Cathy can nearly see the top of Naomi’s legs.

She looks away but finds her eyes keep being drawn back to Naomi’s legs every time she moves them. Naomi crosses and re-crosses her legs giving Cathy glimpses up her skirt. Cathy can see that Naomi is either wearing pale pink panties, or possibly none at all!

Cathy can feel herself getting wet and the muscles of her vagina contract and start to throb. She crosses her own legs and moves her ass around on the seat very slowly. Then Naomi uncrosses her legs and moves her legs apart. Cathy can see all the way up to Naomi’s groin. She squints, trying to make out if she is seeing panties or not. The tingling pulsation of her clit gets stronger, and she nearly leans forward to get a better look, but restrains herself just in time. Then the bell goes for the end of the period.

Cathy needs to know if Naomi has been deliberately putting on a show or if it was just carelessness. She tells her to wait behind after class and Naomi comes up to stand in front of her desk.

Cathy asks her if she’s OK and how things are going with the work, all the time looking carefully at her expression. She’s looking for any signs of amusement or guile, but Naomi just looks slightly confused at her questions. Cathy is satisfied that Naomi doesn’t realize the effect she’s been having and tells her to go to her next class.

Naomi returns to her desk, picks up her stuff from it, and bends at the waist to put them in her bag. Cathy is presented with a glorious view of the bottom half of Naomi’s perfect little ass cheeks with a ribbon disappearing between them; she was wearing a thong! Cathy feels her whole groin engorge with blood and flood with her juices, and she’s almost overcome with the desire to touch herself. After what seems like minutes but is probably only seconds Naomi stands up and leaves the room.

When the door closes Cathy’s hand goes immediately to her pussy and she pushes two fingers down hard on her clit through her clothes. She sits like that for minutes, watching the window in the door to make sure nobody’s looking, then she goes to her office, next to the gym, where she has a change of panties.

That afternoon Naomi’s class has gym and it’s the week for Cathy to get them to run around the perimeter path of the playing field, which the girls hate but, never mind, it’s good for them!

All the girls are ready except Naomi, so Cathy goes back to the changing room to see what’s going on.

“Come on Naomi, what’s keeping--” Cathy begins to say as she comes into the room. She stops short as she sees Naomi slowly pulling up her shorts. She can see the front of the pale pink thong clearly now. They’re slightly translucent and pulled up tight; Cathy can see Naomi’s neat slit running up the center. She gulps and again feels a pulsing in her vagina. Naomi’s pussy disappears behind her shorts and Cathy lets out the breath she hadn’t even realized she was holding.