Huge g-forces rocked you down to your core as Lillian finally got up from her beach towel. She began to walk towards the ocean, where Jen was waiting and waving her arms excitedly at her.

“Come on, the water feels great!” she beckoned.

You couldn’t help but notice Lillian had an extra spring in her step. As the incredible stomps of her legs stepping on the sand created tremors travelling up to her waist, you could also feel an elastic bounce accompanying them. Lillian’s plump booty meat was jiggling up and down as she walked, swinging freely from her swimsuit with the motion of her hips. You knew she was doing this on purpose. One, because she was in a good mood, and two, because she wanted you to feel the unforgettable weight of her ass.

It was true, even though you were wedged tight against her asshole, you could feel every bouncy motion coming from Lillian’s butt cheeks. The massive meaty mountains danced behind your back like two tidal waves of flesh, crashing into one another one powerful step at a time. Like the world’s biggest pendulum they rose and fell, the pressure flattening you against her swimsuit and into her gassy hole. Lillian’s thick tree trunk thighs pumped her legs forward, lifting the massive weight of her backside skyward so it could come toppling down on you once more. She wiggled her hips playfully, adding an extra swaying motion to the ordeal. All she was doing was performing a little strut on the beach, and yet for you the results were outrageous.

Then you felt a force push back. An actual resistance caught the movement of Lillian’s humongous thighs and slowed them down. Being so helplessly wedged against your giant friend’s ass flesh you could actually detect the motions surrounding her body. It’s like you were part of her skin now, a thought you really didn’t want to think about, considering your location. The wave-like pattern was instantly recognizable, even with the gigantic jiggling of her ass cheeks being a distraction. She had entered the ocean water.

The cool emerald waves splashed against Lillian’s legs, spraying pleasant water droplets all over her beautiful skin. She had finally caught up with Jen, who had been waiting to splash her for a while already. Lillain fought back of course, cupping both hands under the sea’s surface and sending the salty water flying back across Jen’s ample chest. They both laughed together as a small pool happened to form in Jen’s cleavage.

As the girls played around outside, a terrifying thought entered your mind. What was going to happen if Lillian’s ass was submerged underwater? You were plastered firm against her bootyhole by her tight swimsuit, with barely any space to wriggle around. There wasn’t any feasible way for you to crawl away to freedom so if Lillian decided to hold her ass underwater for too long… Your heart started to thump like a drum in your chest. There was a very real possibility you could drown in here.

“Too bad Blaise is missing this!” Jen said as she swam deeper into the water.

“Ha ha, you can say that again.” Lillian laughed, following her.

A big wave of water splashed against the underside of her buttcheeks, tickling her skin. Sunken deep beneath her flesh you were really starting to panic. What would happen if all at once the ocean water came rushing into her ass crack? You’d be trapped, completely without oxygen, for several minutes at least. Although it was the last thing you wanted to do, you began to slam your tiny fists against her butthole, screaming at her to stop walking. Her giant oily pucker twitched back in pleasure, smearing its stinky folds against your body.

“She must be able to feel me down here! So why isn’t she stopping?!!”

Lillian’s butthole clenched again in response to your desperate movements. Her giant legs shook with more massive tremors through her backside as she continued to walk into the water. The booming stomps felt like a bell tolling for your own doom. You shouted in dismay, she wasn’t slowing down at all. The huge waves rocked into her body, you could feel the ocean’s surface creeping up her hips. One last bout of water crashed into her waist, you could feel the tide pull her ass under, and then…!

Nothing. You had expected to be flooded with seawater by now, but Lillian’s ass crack was still as dry as ever. Well, maybe “dry” wasn’t the right word for it, since you were covered in sweat and other gross bodily fluids, but the point was you weren’t drowning. The current undulated through her humongous ass, rocking it like a submarine. You could actually hear the muffled ambiance of being submerged below the surface. It was absolutely unreal, Lillian’s ass was so plump and thick that it was acting as a barrier to keep the water out.

You didn’t know whether to love or hate her ass right now. On one hand it was the only thing preventing you from drowning, but on the other hand it was the whole reason you were stuck in this mess in the first place. Lillian continued to walk, her massive jiggling ham planets rocked back and forth while continuing to keep the water out. It was kind of impressive just how big her booty was when you thought about it. Any girl with less voluptuous curves wouldn’t have been able to pull this off. A twinge of annoyance came across your face at that realization. Did Lillian put you through all that worrying JUST to show off how big her butt was?!

Lillian chuckled to herself as she felt you punch her sensitive ass crack. She was absolutely doing this to flaunt her assets in your face. What better way to get you to appreciate the sheer size and scale of her gorgeous booty than to have it act like a makeshift submarine? As long as she kept her thick butt cheeks pressed together you’d be safe from the ocean water coming in. And if somehow that managed to happen anyway there was always plan B…

“Hey check this out!” Jen said to Lillian from just up ahead “I think there’s a school of fish down here.”

“Really? Let me see!” Lillian said as she came over to take a look.

By Jen’s side, Lillian bent forwards to see the school of fish. With the sun brightly reflecting off the waves it was a bit hard to get a glimpse at first, but as she leaned closer she could actually see them. It was a small group of silver and blue ones, their tiny stature made them look like little babies. Getting to watch the fish came with an unintended side effect however... As Lillian bent forwards she moved a little too far, and it caused her massive ass cheeks to spread apart underwater.

The gap between them was only a little bit open, but that was all the space that was needed to allow the ocean water to come spilling through. You screamed as the crashing waves engulfed you, filling the tight cavity of her ass crack almost instantaneously.

“OH GOD FUUUU-BLUGBLRGGH!!”

By the very next second all that was coming out of your mouth was bubbles. This was it. You didn’t have any more chances left anymore. Your tiny body was trapped up Lillian’s ass crack and thanks to her letting her guard down you were going to drown. Her big round rump was going to be your tomb. In a last ditch effort you wriggled as hard as you could, trying to do anything to escape the tight grip of her yellow swimsuit bottoms. There was next to zero odds that you would actually make it to the surface without needing to breathe but you had to do SOMETHING!

Scratching against Lillian’s huge butthole, desperate to climb back to the surface, you realized right away that you were screwed. You were expending a huge amount of energy and making no progress at all. Her bikini was too tight, and her ass cheeks were too big. Worse yet the monumental asshole clenched in response from your struggles, pressing hard against your tiny body. Your heart raced as you thought of what else you could do. Your lungs ached for air, anything!

Thankfully your plight had not gone unnoticed. Lillian felt your tiny nub going off into a frenzy against her anus as soon as the water hit. What felt like forever to you, given your heightened sense of danger, was just a few seconds for her. She knew that you were trapped and without any air, and that she had to act fast.