Barbara and Craig took deep breathes, and dove towards the cliff. Experienced freedivers, they glided through the short tunnel and surfaced in a cave. Sunlight streamed in from above where the roof had collapsed long ago. There was a flat ledge in the circle of light, and the gracefully pulled themselves out onto it. Craig pulled the bag he'd been towing out and spread the matts in it on the rock; they sat on it and took their fins off.
It was Barbara who'd first heard the stories about the cave. She wasn't really dating Craig, as such, more considered him a friend with benefits. They both enjoyed freediving together on the coast and had got to enjoy each other's bodies too. Both were in their mid-thirties but had no desire to settle down. They'd messed around with food in the bedroom, a bit of cholate sauce and whipped cream- her idea, but Craig had liked it. So when she'd talked to him about the rumours of the cave on the island, he was intrigued.
They'd booked a cottage by the bay near where they'd heard the cave was and took the ferry over. A couple of days walking the coast, and diving in the bay, they found where the cave was located. That morning, they got their stuff together and swam out.
Although it was a little chilly, they stripped out of their wetsuits. Both were wearing briefs; they wouldn't usually wear anything under their suits but the rumours were oddly specific. They lay on the matts and Craig pulled his briefs down. He was already visibly aroused. Barbara got to it, taking his tumescent cock her mouth and deftly working it. Immediately she felt a weird sensation in her bikini bottoms. She kept going, and Craig saw green goo oozing from her waistband. The rumours were true! As she felt his cum hit the back of her mouth she felt a small explosion in her panties and slime shot down her legs, up her back and across her belly. "Oh yes!" she yelled, "it works. That feels amazing!"
Craig, having just cum, took a moment or two to take in what had happened. He pulled up his trunks whilst Barbara wiped herself down. "Ok stud" she said to him, "your turn now". She'd taken her bikini bottom off entirely and lay back on the matt. Craig crouched down and put his head between her legs. Deftly his tongue searched out her clit and started massaging it skilfully. As she became aroused, he felt the slime materialising in his swimwear, a deeply weird but definitely erotic feeling. He flicked at her clit and she gushed, being married by a similar gush of goo for him.
Surfacing for air, he rolled over beside her. "Amazing! What even is happening? Where is this coming from?" he exclaimed. "Right?" replied Barbara, recovering from her orgasm. "It's so weird, it's just materialising there. It definitely seems to giving pleasure, rather than receiving."
They lay in the warm sun after Craig had wiped himself down for a bit but the air was still cool. "Well" said Craig, "Shall we see if we can both give pleasure together? I'm getting a little chilly" "Ready to go all the way" replied Barbara. They pulled on the wetsuits they'd worn on the way in. These were both old and much patched, ideal for exploring rocky caves without worrying about getting them damaged, but they also had another medication. Normally they wouldn't need a relief zip, being perfectly ok with just peeing in their suits like all divers, but they had fitted these ones with a crotch zip. They'd tested them out, first on a hot sweaty night in Craig's flat where they made sure the zips weren't going to cause any problems. The second time was a couple of days ago in a secluded cove, a misguided fumble on a beach that reminded them that sand is never welcome in sex.
They helped each other zip up their hooded suits slowed somewhat by their insatiable desire to fondle each other. They unzipped each other at the crotch and reached inside. Whilst Craig fingered Barbara, she caressed his cock. They were used to each other's rhythms and slowly started arousing each other. As they did, the already slimy feeling wet wetsuits started feeling slick inside from their heads to their ankles.
They sank to their knees as Craig became erect and he felt Barabara becoming wet. He lay back and she mounted him as slime seeped from the open parts of their suits. They thrusted and grinded, being careful not to make each other cum for as long as possible. Green gunge poured from the hoods of their suits onto their faces, squirted from the ankles and wrists and flooded their crotches. Eventually they came together in massive orgasms, at which whatever was producing the gunge went into overdrive. Their suits swelled so much Barbara fell off Craig. Gunge sprayed out, fountaining from between their legs.
Eventually it subsided, leaving them lying together in a pool of slime. "Incredible" exhaled Barbara. "Just, wow" replied craig, barely able to think. They lay there for some time, talking over what had just happened to them. Neither could explain it, but both loved it. "We've got to come back here again" said Craig "that was wild." "Sure, that was beyond expectations" replied Barbara. "Shall we go though?" they packed up the mats, slipped on their fins and plunged into the water. The tide was rising and would cover the ledge soon, washing away the remains of what happened there. They swam back to the beach in front of the cottage, suits still full of slime. They walked up the beach and round the back of the cottage. Stripping out of their suits, they beheld each other- head to toe, other than their faces, coated in green. They grabbed each other and fell on their suits on the floor, fucking there and there in the backyard.