Previously, Will and his mother had pushed their taboo experiments further, only to be caught in the act by his sister, Devin. Will and his mother now try to navigate the aftermath of the encounter in their own ways.
***
Devin sat with her toes in the water as she watched her younger brother sweep the shore of the pond for more rocks. She had left for college just a year ago, and was on her summer break. Will bent over, inspecting a likely looking stone, before discarding it and moving on as his sister surreptitiously admired how her baby brother had grown to fill the small swim suit he now wore. She'd originally planned to come home for a few days to say her hellos, pack, and then promptly leave on a trip to the beach with some girlfriends. When she'd arrived home and seen what debauchery her little brother and mother had been up to though, she'd decided she needed a change of plans.
***
She thought back to a few days ago. She'd opened the front door, loudly announced herself, and for a wonder was ignored. Her mom, usually all too eager to greet her firstborn, was nowhere to be found. Instead, Devin heard the sounds of some old, but clearly sensual, music and cautiously crept her way toward the source. She poked her head around the corner and watched as, view partially obscured by an obnoxious potted fern, her mom put on the most erotic striptease in a scandalous bikini. It wasn't that her moves were the most refined, but something about the pure-hearted passion and single-minded focus elevated the performance. Devin subconsciously reached between her legs, lifting up her skirt to rub fingers against an increasingly wet satin-clad mound. She wondered who the lucky guy was to be getting so much of her normally conservative mom's affection-- it seemed unlikely it was Dad, as he never seemed to go much for that, and should probably be at work anyway. She caught a glance of the stranger's dick as her mom began to straddle him. Perhaps slightly longer than average, but exceedingly thick and fully waxed just as she liked.
She admired her mom's dedication to the tease, as even as she was clearly about to orgasm herself she continued to only let the tip of the man's cock inside her. Devin felt an unusual urge to lick her mother's juices off the handsome stranger's cock. When had she ever felt like that about a woman? And her mother no less? She rubbed herself more furiously, sliding a finger into her slick wetness with ease as her mom got to her knees. She stifled a groan herself. She almost lost her rhythm when she heard the baritone voice "Finish me mommy." Ignoring own nascent incestual tendencies, she assumed that her mom was just engaging in some very dirty roleplay and damn was she there for it. She felt the pleasurable sensation between her legs reach a climax, as her tightly squeezing thighs arrested the movement of her fingers in what was undoubtedly the most powerful orgasm of her life.
A few moments later, as she watched her mom get positively saturated in cum, she decided she absolutely had to sneak a riskier peek and see who this well-equipped stud was. She lifted the fronds of the plant that had been obstructing her view of the man's face and promptly performed a spit-take, careening backwards as she knocked over her luggage in a clatter. Her mother and sibling no doubt thought her exclamation was in shock that they were doing such depraved acts together, which she was happy to encourage at the time, but having had a day to process the situation she'd determined she was unbelievably jealous of both of them.
***
Back at the pond, Will brought his small collection of skipping stones and sat next to his sister. Medium height, blonde hair past her shoulder blades, breasts that were just short of being large but with a petite waste, and a cute smattering of freckles across her face, he'd once heard a friend describe her as the 'ideal girl-next-door'. He and his sister had always been close before she left for college, but now, whether it was due to the year of absence or the... unfortunate event she had witnessed, he had felt as if a wall had formed between them. His mom was currently trying to drink her way into forgetting what they'd been doing, and had encouraged him to try and make up with his sister. Hence the trip to the nearby pond. He skipped stones as he tried not to leer at his sister. She'd always been a sight, but having had a year on her own to grown into her own skin, she'd really become a beauty. It didn't help that she'd insisted on bringing a towel and tanning in a swimsuit that he was certain his mom didn't know she owned. He awkwardly avoided eye contact with her. If he knew his sister at all, he knew her sweet nature would practically require her to forget her own discomfort and disgust with him and probably chose this exact outfit and outing just to assure him that she trusted him. He wished he was worthy of that trust right now, but as she rolled over onto her front and untied her top, he immediately cut his eyes over looking for a glimpse of anything revealed in the motion. She seemed completely peaceful, completely exposed save for the small Brazilian-cut bikini that, with each shifting of her legs, seemed to be swallowed up more and more by a well-toned ass.
Eventually, she asked him if he would reapply some sunscreen to her backside. He lifted a small prayer of thanks to the gods even as he inwardly cursed his weakness. He would take a great deal of enjoyment out of this, but he would restrain himself. Irreparably damaging the relationship with his sister was not worth a few moments of being extra gropey. Still, as he clambered atop her, cock tucked into the waistband of his swim trunks to avoid inadvertent stabbing, she let out an enormous sigh as he massaged the lotion deep into her as they both entered trance-like states.