“Hey look, this’ll do,” you say, and plump your bag down on a four-seater table. It’s good to get a table to ourselves, although this mid-week afternoon train from King’s Cross is almost empty. It’s much nicer than travelling at the weekend, when the train to Edinburgh is often packed. It was a good idea of yours to get to our friend’s hen party this way, rather than drive. It’ll be more relaxing, and no need to worry about still being over the limit when driving back afterwards.

For the first half an hour or so, as the train speeds smoothly northwards, we each happily do our own thing. I alternate between reading my book and looking out of the window, watching the landscape flash past. You text a few people on your phone, then fiddle about in your bag, but you don’t seem able to settle down to anything.

After a while, you start playing footsie with me under the table. I smile and respond, stroking my foot up your leg, teasing you. You do the same to me, but go further, sneaking your foot up under my skirt and rubbing against my thigh. You’ve kicked your shoes off, and your bare toes feel rough against the skin of my legs. It’s nice. Your foot ends up on the seat between my legs, pressed against the crotch of my panties. I wriggle against you, enjoying the gentle stimulation. I suspect you’ve been feeling a bit horny all day, and now I’m starting to feel the same way. My boyfriend doesn’t mind if I have a bit of girly fun, and I don’t suppose yours does either.

I eye you across the table. You’re wearing a plain white blouse, but it’s quite tight and your large breasts look quite snug inside it. The way you’re leaning against the table is squeezing them together, putting a bit of a strain on the top two buttons. Casually, I push my bag to the edge of the table, which acts as a sort of shield. Then I put my arms on the table, before reaching over and stroking my hand over the curve of your left breast. Gently I start to knead it, then squeeze slightly harder as you smile. You peer around to make sure no-one is watching, and I can feel your nipple getting hard inside your bra. I love the way your breasts move as I stroke them.

Getting bolder, I insinuate a finger between two of the buttons, and feel the lacy surface of your bra against my finger. I wriggle it up and down, getting two fingers underneath the mound of your tit and bouncing it up and down. This is fun, but your bra is getting in the way, and that’s starting to frustrate me.

I lean across the table and whisper, “Go take your bra off.”

You act shocked. “No way,” you say.

“Go on, do it. I dare you!”

“Damn it, Annie, you’re dreadful.”

But you slide out of your seat and head off down the aisle towards the toilet, taking your bag with you. A few minutes pass, and you’re back.

Mmmm, nice. Without your bra, your large breasts seem almost out of control inside your tight blouse. They swing loosely as you edge back into your seat, and between the buttons I can see glimpses of the pale skin of your chest. I lean over and gently knead your breast through the cotton top, the flesh moving under my touch, feeling loose and supple now it’s not supported by your bra. I can see the dark patches of your nipples, and let my fingers slide over the right one. Almost immediately it gets hard, pressing against the material. I tweak and rub it. You are flushing slightly, little beads of perspiration breaking out on your forehead. You’re embarrassed at how aroused you are getting, and I wonder if you’re going to pull away.

But instead you lean forwards, letting your breasts rest on the table, your hands clasped nervously in front of you. My bag on the table is still shielding us from view, at least partially. You’re biting your lip, getting more excited. I wonder how far you are willing to let me go. I leave your nipple and find the button closest to your breasts. I start to push it through the buttonhole. Your eyes widen, and you put your hand on my wrist.

“No way,” you whisper, a pleading look on your face. “You can’t!”

“Why not?” I murmur, and with a little “pop” I push the button through the hole. You gasp softly. The sides of your blouse hang apart, and I can see more of your skin and the full curve of your breast. Gently I stroke the edge of your soft tit. You close your eyes, your breath catching in your throat. Slowly, daringly, I slide the edge of your blouse across, revealing more of the front of your breast.

“Annie, what...” you whisper urgently.

“Shhh,” I whisper back, interrupting you. “Just keep still!”

As I pull the front of your blouse open, I see the edge of your dark areola peeping out, then (oh wonderful) the rest of your nipple, followed by your whole bare breast. I hold the front of your blouse open with my thumb and fingers, the top button straining. I spread my hand over your lovely tit as it hangs out. It’s so exciting to see it exposed like this, smooth and pale and vulnerable. I can feel it moving as your heart beats faster.

“Oh Jesus, Annie, please no.”

“Oh babe, what a lovely boobie,” I whisper with a smile, squeezing it with my hand.

I lean across the table, looking into your eyes as you lean into me, trying to hide your bare exposed breast in the space between us. I circle your erect nipple with my finger, the pink bud harder than I have ever seen it before. I squeeze it, stiff but flexible, like a nodule of rubber. You gasp.

“Christ, Annie.”

A movement behind you catches my eye: a woman is walking down the aisle towards us. I push my bag so that it covers your exposed breast, but give your nipple an extra hard squeeze as she walks past. You let out a little squeak and kick me hard under the table.

As she disappears behind me down the aisle, I pull the bag away, but leave my hand where it is. I love the feel of your nipple. Your cheeks are pink, but I can tell it’s as much with excitement as embarrassment. You’re nervous, but massively turned on.

I lean over and whisper to you.

“I dare you to go down to the buffet and get a coffee, just as you are.”

“You’re kidding!”

“Ok, you can tuck your tit back in, but you have to leave the buttons undone.”

You bite your lip and nod your agreement. As you shuffle sideways out of your seat, your bare breasts swing from side to side inside your almost unbuttoned blouse. Taking your handbag, you walk off towards the buffet, using the seat backs to steady yourself against the movement of the train.

While you’re gone, I slide my hand under the table and press it against my plump mound, pressing and kneading it, feeling my clitoris tingling. I pull my dress up at the front and push my hand underneath. I push a finger round the edge of my panties and slip it between my labia. I take it out and look at under the table, glistening with my sticky juices. I casually lift it up and smell it, before licking it, tasting my tangy pussy juice. The game has got me at least as turned on as you.

You seem to be taking an awful long time. I’m almost getting worried, when suddenly you’re sliding back into your seat, carrying a couple of coffees and a brown bag.

“I got you a treat,” you say, giving me the bag. I open it, and see a packet of biscuits, on top of what I think at first is a bright red napkin, but realise with a thrill is a pair of knickers: your knickers.

I put my hand into the bag and feel them. I can see there is a damp patch on the crotch.

I smile at you. “They’re a bit wet.”

You blush.

“I got so turned on, standing in the queue,” you say. “On my way back to my seat, I slipped into the loo and took them off.”

“Did anybody notice you had no bra on?”

“There was this guy, I think he noticed straight away. He was standing behind me and I’m sure he was looking over my shoulder down the front of my blouse. I felt a bit embarrassed at first, but as I stood there in the queue the thought of him looking at me, and enjoying the unexpected treat, began to get me excited. I thought what fun it would be to tease him a little, so I leant over so the front of my blouse gaped open. I felt my bare boobs swinging loose, and I knew he’d have been able to see the whole of them if he looked down. I had a quick look myself and my nipples were just so hard. I wondered if his cock was hard too, and I imagined him ripping my blouse right open, pulling up my skirt, dragging my knickers down to my knees, and fucking me right there, in front of everybody. Just getting his hard cock out and sticking it into me, fucking me until he squirted his cum right up my cunt. Then he’d pull it out, stick it back in his trousers and leave me standing there, his cum dribbling out of me and trickling down my legs.”

I can tell how aroused you’re getting as you tell me about your dirty little fantasy. You’re blushing, and I can see your nipples are still hard even now; little dark, hard peaks pressing against your blouse.