There was only one person outside the church gates, so it had to be her. I was five minutes late, and she had the look about her of someone impatiently waiting for someone.

I didn’t cross the road. Instead I took out my mobile. The message I sent was succinct. “I’m here.”

Her name was Kate, or at least that’s what she claimed. She was wearing a knee-high pencil skirt and black nylons with three inch heels. It was warm enough for her to have nothing but a dark blue top above the waist; short sleeves, neck high, but tight enough to set the imagination racing. Dark curls courted her shoulders, and she adjusted her glasses before tapping on her own phone.

My mobile pinged, and there was a flutter of excitement in the pit of my stomach as I accepted the request. Kate was already crossing the road, paying me no attention as she made her way into the station, but then why should she? She didn’t know what I looked like.

Down to the tracks; Northern line, northbound, Charing Cross branch. Not rush hour, but plenty of people nonetheless. Kate found a seat between a woman with a huge swollen belly and a tough looking girl wearing thick make-up and metal piercings. Happily the seat opposite her was available, next to an elderly gentleman. For the moment the seat to my right was unoccupied. I waited for the doors to close before making my move.

As the train plunged into the tunnel, I slid a finger across the screen of my mobile, watching Kate carefully. Her body tensed, then she acquired the look of someone trying hard to exert self-discipline. It was working. A sense of both triumph and relief ran through me. I’d only downloaded the app yesterday, and had been terrified that it wouldn’t work – or be terribly complicated.

It wasn’t, but I didn’t want to move too fast and killed the vibrations. Kate was staring straight at me. Had she twigged it was me? It seemed highly likely. I locked eyes with her, then lowered my gaze, staring brazenly at the tightly held shapely promise beneath her top, at the knees that touched where the hem of the narrow skirt ended. Then I returned my finger to the screen, swiping randomly.

Kate started. The women on either side of her either didn’t notice, or pretended not to, the way people do. There was a parting of raspberry tinted lips. My cock swelled as I allowed myself to revel in the knowledge of what was happening under her skirt. To avoid the bulge being seen by others, should anyone actually bother to look, I slipped a hand into my pocket and pressurized my indecency. Opposite me, Kate had assumed a vacant stare; her body swayed to one side, and it looked like an effort on her part to bring it back upright.

I stopped the vibrations, giving her some breathing space. She shifted slightly, looking up and down the carriage before looking at me again, as if daring me to do my worst. I let her wait for it as we pulled into the next station. A young woman sat down next to me. Then we were off again.

This time I kept the vibrator active for the full two minutes it took to reach the next station. Kate’s eyes opened and closed at intervals. Her bosom shifted with each breath, nipples clearly outlined under her top. Her legs shifted slightly as she gave every impression of being on the verge of abandoning all decency and restraint. As the train pulled into the station, her hand came up to her mouth. And I denied her what I imagined was coming, or perhaps saved her from making an exhibition of herself – it depends how you look at it.

There was a lot of movement. People crowded into the carriage, blocking my line of sight. Nevertheless I entertained myself with the toy all the same, switching the vibrator on and off at intervals. In some ways it was better like this, with fleeting glimpses of Kate. I could choose fast or slow vibrations on a whim, then wait for bodies to shift, catching a glimpse of lips parted in arousal and eyes closed in pained delight, her tense body fighting the urge to reveal beyond a shadow of a doubt what was going on, possibly convulsively.

Stations came and went, passengers changed. I didn’t care who sat next to me, or who sat next to Kate, or who was in the way. During a whole stretch between two stations, I left the vibrator inactive. Kate knew it was me now, I was sure. A man moved slightly, and I could just about see her between two bodies, staring straight at me, expectant, demanding. I aimed the phone at her, but refused to give her what she wanted.

Not until the train next accelerated into the tunnel. I had a nice view of her again, between a summer dress and navy blue trousers. A sudden burst, a shock to her system; fast, urgent, demanding vibrations. Kate started violently. Still nobody seemed to notice, and even if they did, instinct would probably compel them to pretend otherwise. I could choose the highest level, force the most obvious reaction from Kate. Instead, I adjusted the speed downwards, making sure it was no more than a ripple, but a sustained ripple as bodies once again hid Kate from view.

New station. People moving. Kate staring at me, eyes gleaming. Eyes closing as I gave her a quick, violent burst; lips parting, tongue swirling. Kate squirmed as an overweight guy in a baseball cap plonked himself down next to her.

Bodies in the way. I brought the speed back down to a ripple. I pushed down on my erection, imagining I was scarcely less aroused than she was. I loved the pencil skirt, but simultaneously longed for her to be wearing something that allowed me a glimpse above the knee. Part of me urged caution, while another part wanted to see her climax, right there, in front of all these people, sandwiched between people.

No-one would notice. No-one ever notices anything.

Next station. Kate suddenly on her feet. Time to stop the vibrations and get to my feet myself, jostling other people aside to follow Kate off the train, joining the throng heading for the lifts. Getting into the lift behind Kate.

We were right at the back, and I couldn’t help myself. Everyone was staring straight ahead. Everyone except me. I was looking down, at the graceful curve of Kate’s buttocks where the pencil skirt held them in a firm embrace. I put out my hand. I touched one of them, running my hand over the full exquisite curve. The lift came to a stop. I gave a quick squeeze.

Kate moved. Out of the lift, out of the station. She crossed a busy street, then turned into a side street. I followed at a distance, curious as to where she was going, refraining from activating the vibrator, as much as I wanted to.

We walked for five minutes, until the street broadened out into an open space by a palatial looking church. A fence and a low wall marked out the perimeter of the churchyard. Six benches and three red phone boxes – presumably there to please tourists more than anything – were lined up in front of the wall; four of the benches mostly occupied by what looked like students. Kate chose an unoccupied bench sandwiched between two of the phone boxes and rummaged in her bag. I stood a short distance away, not caring if she saw me or not as she brought out a cigarette and lighter.

With the first drag she crossed her legs. She wasn’t looking at me or, it seemed, at anything very much. I didn’t blame her, the view behind her may be impressive but the view in front wasn’t terribly inspiring. I imagined she’d appreciate a resumption of the fun. I brought my mobile back out, sliding a finger across the screen to manipulate the vibrations. A soft ripple at first, then a steady increase in speed and intensity. Kate tried to appear cool and collected, but there were tiny signs as she sat there, smoking her cigarette.

A much harder burst. Kate’s body swayed, her legs came uncrossed. That was the way to do it; hard bursts, five seconds apart. Kate ditched the cigarette after the third burst. After the fourth her body lurched to one side, her eyes closing and her mouth opening wide before she put a hand up to it.

She looked straight at me. I killed the vibrations, but when she got up and started to walk I decided to try letting the vibrator ripple softly as she walked. I imagined she looked a little less steady on her heels now. Perhaps that was why she didn’t walk far, to a neighbouring square, making it to the far end of the central garden before settling on a bench. Its nearest neighbour was unoccupied, but a trio of students were lounging on the grass not far away, though they paid Kate no attention.

The bench was partially concealed by trees, but could certainly be seen from some of the windows of the dismal looking seven storey building at the back of the square. But who could see or not see no longer mattered to me, as I stood no more than ten yards from Kate and slid my finger across the screen, bringing the vibrations up to not quite full speed.

Kate’s mouth fell open. She clenched her bottom lip with her teeth. From the look of her, I imagined she was forcing her thighs together, yet her hand moved in her lap as if she was desperate to touch herself. I slowly lessened the speed, only to then zonk the thing right up to full. Kate started so heavily that her buttocks lifted from the bench. I wished I could make the thing go faster, but this was good enough. Kate was squirming violently. Her mouth was wide open. I could make out groans that sounded as if she was fighting a losing battle to curtail them. The phrase, “her eyes popped out of her head,” suddenly made sense to me in a way it never had before.

Her body lurched, as if she’d fallen faint. She was almost lying on one side when she began to convulse, as if she were having a fit. I forced myself to look around. Incredibly the students hadn’t noticed a thing. I stepped towards the bench, only extinguishing the vibrations once I’d sat down next to the hyperventilating Kate.

Eventually she sat up straight, delving straight into her bag. I brought out my own packet of cigarettes and proffered it. “Allow me.”

Kate extracted a cigarette with pointed, cerise nails. I gave her a light before lighting one of my own. The woman took a heavy drag. “That was very naughty of you,” she said.

“I thought you wanted to cum.”

“Touching me like that in the lift.”

“You never said I couldn’t.”

“I never said you could.”

We sat in silence, for about a minute, sucking on our cigarettes, watching the students joking amongst themselves. Then Kate spoke again.

“Do you want to know a secret?”

“What?”

“There in the lift. When you touched me. If you’d have asked, I’d have let you fuck me.”

“What, there in the lift?”

There was a wisp of a smile. “We’d have had to find somewhere more private.”

I waited, taking a drag. “And what if I asked you now?”

“You want to fuck me right here?”

“We’d have to find somewhere more private, of course.”

Kate exhaled, blowing near perfect smoke rings. “Sorry. The moment’s passed. Besides, I’m married, remember? I can’t go around letting random strangers fuck me.”

I felt disappointed, cheated almost, though I didn’t know why, since actual coitus had never been part of the deal. Kate flicked the stub onto the path. I dropped mine and ground it into the dirt.

“Mind you,” Kate said suddenly. “Now you’ve seen me cum, it seems almost rude of you not to let me see you cum.”

“What, here?”

“You could stick your hand down your trousers. Nobody would notice.” That seemed entirely likely. I was considering this when Kate continued, “Or maybe I have a better idea.”

“What’s that?”

“Follow me!”

I followed her quite literally, about ten yards behind. She led me out of the square, past another square, this one with a hotel that looked as if it regularly played host to illicit trysts, but there was no stopping here. No, on to a busy street, to a bus stop. We waited, pretending not to know each other, though I wasn’t sure why. I couldn’t resist it, I activated the vibrator, just a ripple, just to keep her interest kindled.

We took the first bus that appeared, the number 68, destination West Norwood. I climbed aboard behind her, then up to the top floor. She moved right to the back, just behind a young woman with straggly red hair and a t-shirt with some kind of slogan on it who seemed deeply engrossed in her phone, the way people are. Kate indicated for me to sit next to the window. I could see her point.

Sitting next to me, Kate leaned across, her breath moistening my ear. “Do it! I want to see you cum, imagining yourself fucking me!”

We were safe. No-one was looking back, of course they weren’t. I pulled in my stomach and stuck my hand down my trousers and into my underpants. The only thing that would have made my cock happier was if it had been Kate’s hand.

I glanced at her. She was staring at my lap, at the movement in my trousers. I reached out with my left hand, placing it on her skirt, her thigh, squeezing lightly.

She hadn’t said I couldn’t touch her; nor had she said I could. The fact that she did nothing to move my hand away spoke volumes. I squeezed harder, wishing I was touching nylon but knowing I was lucky to be doing this much, as I used my other hand to squeeze my cock between fingers and thumb. Kate’s eyes flitted between my face and my trousers. I fancied that the muted but relentless vibrations were having the desired effect on her; her eyes seemed to be glazing over, just a touch.

I didn’t have to imagine fucking her. The feel of her thigh was enough; being allowed to touch, squeeze, fondle. It was enough to see her watching the movement in my trousers as I rubbed my hard cock; enough to know that the vibrator was doing its business on her.

Things were never going to take long. Heightened arousal had been my companion for a while now. Besides, as the bus pulled away from the third stop, Kate leaned in, soft breath snaking its way into my ear. “I’ve changed my mind again,” she whispered. “Woman’s prerogative. I’ll let you fuck me right here, right now, if you want to.”

That was all it took. A sound that was a dead giveaway rose to my throat, and I disguised it with a cough, forcing myself to stifle any further moans as I began to spurt, digging my fingers into Kate’s thigh. She smiled wickedly, staring at my face all the time, watching my expression carefully as I spilled two heavy bollocks’ worth of thick semen in my pants. The redhead in front of us fidgeted slightly. If only she knew.

The bus was approaching the next stop. Kate rose, without physically removing my hand. “Don’t be a stranger,” she said.

Then she was walking down the aisle, a little unsteadily, I thought, but maybe it was the movement of the bus. I didn’t bother to adjust the vibrations. After all, she had the power to stop them if she wanted to, but I hoped she wouldn’t for a very long time.