The picture arrived on my phone with her accompanying message:

This one?

I tapped, made it full screen. Gasped involuntarily. The deep blue off-the-shoulder dress brought out the same colour in her eyes, dark tresses cascading forward into the lens, backlit by the changing room bulb.

Hell yes, I typed.

You don't think it's too short?

Nothing is too short on you.

Shoosh, you. Can't upstage the bride.

Throwing the tennis ball into the grassy middle distance, I watched my dog scamper after it, my wife playing peek-a-boo with our daughter a hundred yards away.

I tapped in: Show me the back.

The dog returned, joyous and triumphant, dropping the ball at my feet for me to toss in a different direction.

The next picture was more stunning than the first. Clara, glancing mischievously over her shoulder, the hem at the back raised an inch with one hand. Toned thighs led down a mile of leg to strappy heels. Truly the finest woman I'd never touched. At least, not physically.

My fingers quivered as I typed: Perfection.

The dog dropped the ball at my feet and I stooped to pet his side, then arced the ball away once more.

An idea formed. I think the dress would look better lifted at the front.

I waited, lazy summer sun inching higher above the park filled with laughter and carefree shouts.

My phone pinged. Nice try!

I smiled. Need to know what's underneath so I can picture my face there.

One word popped onto the screen. Fuck.

That was my cue. I hurled the returned ball again then typed: Touch yourself, Clara. Right now. Slide your hand into your knickers. Make yourself wet for me.

There was an agonising delay. Was she doing it? I jigged my leg, glanced over at the idyllic scene of my wife and child playing in the sunshine. Felt no guilt. Felt guilty for it.

Her message drew my focus. I'm already wet.

I nearly dropped the phone at the thought of diving beneath the dress to discover that revelation. Tongue exploring the material, inhaling her arousal, the dress billowing over my shoulders as I clutched her bottom and pulled her to my mouth, giving her a thousand more reasons to soak the garment.

My fingers quivered. Picture, or it didn't happen.

The dog circled my legs and I scooped up the ball, "There you go, boy." I threw it and the terrier raced off.

I stared at the screen, willing it to change. Aching for the next message.

It pinged. I tapped.

Gawped.

Pinched out to zoom.

Her fingers, spread, two strings of silvery grool looped between them; one perilously close to her wedding band. I imagined taking the digits in my mouth. Sucking her clean, my eyes on hers the whole time, then lifting her dress and seeking the sticky source.

The phone shook as I tapped away: OMG. Keep going. Finger yourself until you cum for me right there.

Blood roared in my ears as time stretched out. The bark of the dog and happy park chatter faded into the background as my imagination went into overdrive. Clara, leaning back against the cubicle wall, one hand clutching her phone with its lewd encouragement, the other deep in her dripping cunt, thumb working her clit, until she was biting her lip and fighting to stay quiet in the curtained enclosure.

My thoughts turned to what I'd do if I were there with her. I'd leave her panties in place, closing my lips over the wet lace to soak up as much of her juice as I could, all the while grinding my face into her sopping snatch to generate more for my greedy mouth to devour. A glorious catch-22.

My cock hardened fully in my shorts as I threw the ball once more, on autopilot while my mind was elsewhere. The next ping and subsequent picture made pre-come ooze and seep into my underwear. There was no text. It wasn't necessary. Her phone was out front and angled down. The pristine dress had been hiked to her waist and her hand was inside her panties, fingers visible through the wet lace, lying against her clit. Fuck.

Cum for me, Clara. Now. And prove it.

I trembled as I hit Send, not entirely sure the effect her next message would have on me. I was already leaking pre-come profusely. Any more would potentially seep through my shorts, exposing my hidden yearnings.

"Honey?"

I blinked up at my wife, a few scant yards away, her quizzical smile sending my now hyper-alert brain spinning for a hint of what she'd asked me. The dog frolicked around her legs, yapping.

"Say again?" I asked, shifting my hand to cover my throbbing erection.

"I said can I borrow your phone. I just want to check what time the restaurant opens this evening." She held her hand out.

Everything greyed for a split second. Adrenaline spiked. I numbly hit the browser icon and handed it over, panicking if this was 'that' moment. If we were sunk. She took it and tapped the screen, blissfully unaware of my jittery turmoil.

She was handing it back when I heard it. The ping. My mind replayed the exchange like a relay race in slow motion, as the baton change is discussed. Seconds fragmented as she glanced down at the tone.

Then the phone was in my hand.

"I think you have a message from work," she smiled as she walked back to our daughter. "Oh, 5 pm," she called back, oblivious to my pounding heart.

I stared after her, then at the phone in my grasp. Tapped the message icon and the picture filled the screen, making my pulse thump for an entirely different reason.

Clara, slumped to the floor, knees apart displaying soaked panties. Her fingers were in her mouth, lidded eyes and flushed cheeks evidencing the peak of pleasure. Her four-word message made me question everything:

Wish you were here.

Fuck.