All of the above

Max had a devious little idea run through his mind. He wanted to see just how much stamina he had after he used the what if machine... "Let's stress test this little threesome a bit then." He thought to himself as a wicked grin spread out across his face.

Britney, his mother watched as her studly son stared at her dead in the eyes, took one of his Aunt's (her own sister's!) delicious massive tit in his mouth, and wrapped both hands behind her own head before pushing her down onto his cock. She felt a small orgasm hum through her as she realized her little stud was starting using her mouth at his own forceful pace, while lapping at her own sister's massive milky tit. The view alone made her feel like the luckiest slut in the world. Her sister was getting just as turned on and her dirty mouth started running.

"Ooooh, you like this big heavy tits, stud? You filled them up like this when you pumped your next little slut into my pussy. Sorry they're not giving milk quite yet though, but I don't think you mind, huh? Gonna pump your thick load into your mommy's mouth? Make her taste her own son's cum as you pump it down her throat? God you're such a horny little bastard and I LOVE IT!" She started rubbing her clit as she watched the scene unfold, heat radiating from her sensitive nipple as her nephew sucked at her massive tit.

Max felt his orgasm building and grabbed his mother's head tight and slammed his cock to the hilt down her throat, letting her feel his full balls against her chin as he felt his load rise. She felt his balls rise and clench as his cock swelled down her throat. She couldn't believe she had waited so long for this and was deliriously happy as her studly son started pumping his thick load down her throat.

One. Two. Three... Rope after rope, pulse after pulse, his cum just kept shooting down her throat. Britney felt the world start to go dark as she held her breath, not daring to let one drop escape. She gasped for air as he withdrew from her mouth, feeling the thick heavy load in her belly. No one had ever cum that much before, and she felt it explained how her sister got knocked up so easily. With this much cum, he could breed a city, she mused as she rested on her knees, feeling her stomach, slightly sad her son hadn't pounded it into her pussy, made her nice and pregnant too. Her still recovering mind had thought that him getting up after cumming down her throat was to wash up in the bathroom. No one could cum like that twice and still be hard.

She suddenly felt herself being lifted. She felt herself being brought up to stand, and she wobbled to her feet, still bent over on the bed, resting her head. She peered over her shoulder, and saw her son, half a second before her lay his still hard cock across her ass.

Both sisters were speechless.

No one had done this before. He had just pumped enough cum to supply a sperm bank for months into them. Alison had watched enviously as Max seemed to pump gallons of cum down his mother's throat. Yet here he was, standing behind his own mother, just after pumping both full of cum, still hard as a rock and apparently from the look in his eye, hungry for more.

Britney looked back from her son's miraculously still hard cock to her son's eyes. She felt the hunger in them. The heat. The primal fire that said that this was a man and he is eyeing his woman. The only words that was uttered was a whispered "Please" from her lips before he pulled back, and slammed his hard cock into her soaked pussy in one stroke.

Britney's world was complete. The world went white as she felt places in her being stretched in ways she only felt when she orgasmed as she gave birth to Max, years ago. Now he was back in his mother, stretching her out in ways no one else has.

He began to move, starting slowly, almost as feeling out with his cock the same passage he had been born out of and was now returning to. But as the moment passed, he started to push in again, lengthening his strokes, pumping a little bit harder, a little bit quicker.

Alison watched with her eyes wide, her nephew was now fucking the shit out of his own mother, her sister, and claiming her. She could tell from his determined look in his eyes, he was going to take her, break her with that delicious slut-breaking cock of his, and breed his own mother. Just like what happened to herself, and she felt her pussy drench itself at the thought. Reaching out to her nightstand, she grabbed her favorite toy, a dildo modeled after his cock, and started to push it into herself, before she had two delicious ideas.

With some difficulty, she moved around the bed, bringing her still cum filled pussy to her sister's face as she was being railed by her son. Her little sister looked up, into her eyes with a far away, glazed look that Alison knew all too well. Wordlessly, Britney moved forward a bit and started licking, tasting her pregnant big sister's pregnant pussy drenched in her son's cum. Alison felt her sister's skilled tongue working away at her clit as she imagined the future. Every slut in this house pregnant with Max's children, even the horny little repressed sluts downstairs, her own daughters and nieces, offering their tight little pussies and womb's to this monstrous cock. Knowing her own daughters and neices are probably in their rooms, playing with themselves as they enviously listen to their mothers being fucked- no, Dominated by this stud, wishing it were them being pounded. Being taken. Being bred.

Alison started cumming hard on her sister's tongue as she imagined it, a whole house of pregnant incestuous sluts, breeding more little sluts to worship this perfect cock.

Britney was still in a state of bliss, feeling orgasm after orgasm wrack her body, one flowing to the next as she felt her son pound into her. She loved the feeling of being filled with his cock so perfectly, knowing it was going to pump her full of cum, fill her like the slut she was, and let her do what her body sang for, carry her man's children. God she couldn't wait till she was all gloriously swollen, a fertility goddess made flesh to serve the cock that made her this way. All before bringing another beautiful life into the world so she could be blessed again with his child.

Max was in another world and just luxuriated as his instincts slammed him into his mother's hungry pussy. He could feel his balls churning up a massive load and knew that he didn't have long before he pumped this gorgeous woman full of his cum. Full of his child. The thought of his mom pregnant with his own child, tits swollen even bigger, belly gloriously round, letting the world know she was a bred little slut. He didn't even notice his own thumb slipping into his mom's ass, something she barely felt herself as she had a near religious experience on his shaft.

The view of it all to Alison started pushing her towards the most deliciously massive orgasm she'd ever felt, and she embraced it as visions of her daughters taking this cock filled her vision.

Britney's world, humming with the raw pleasure that wracked her body started building towards it's highest peak yet. She felt an orgasm bigger than any she had ever felt, even back in her sluttiest days with her sister or with Max's own father, and she embraced it as she embraced her new role in life, being her new man's mate, the fact that it was her son driving her even wilder with the naughtiness of it all.

Max felt his body humming as all he felt was the pussy he was plunging in and out of as he felt himself reach that peak as his eyes opened and took in the sight before him. His own mother squirming on his cock as he grabbed her hips from behind to slam himself into her with all he could muster, his aunt spread out on her back infront of his mother, having her lick her still dripping pregnant pussy as she mauled her tits. His cock swelled as his load climbed his shaft, eager to reach the womb he came from.

All three came at the same time, reaching heights of pleasure they had never reached before (even Aunt Alison, and she had combined sex and **** when she was younger). Britney feeling her world complete itself as her son pumped rope after rope into her hungry pussy, knowing he had every intention of breeding her, his own mother, just like his aunt. The thought sent shivers down her spine. Alison's eyes rolled into her skull as the pleasure overwhelmed her, falling back onto the bed covered in her own sweat, as she fell asleep she could almost feel the little girl in her womb twitching, but not quite kicking almost as if she had cum with her mommy as well. Britney fell forward onto the bed, her legs giving out, and landing onto her older sister's legs. She could feel the little one twitching as well, and as her brain surfed the afterglow of some epic orgasms, she wondered if this little slut was already loving her daddy's cock from inside the womb.

Max staggered next to the half conscious women and flopped onto the bed as well. While during the most amazing sex of his life (albeit while he didn't have that much experience yet, technically), he hadn't felt tired or any pain, he sure felt it now. His hips, abs, and balls aching from the workout he had just gone through, but he didn't regret a second of it. If anything, it resolved him to really think about how to have a lot more fun like this with the 'what if' machine and all the horny little sluts downstairs, if his mom and aunt are any indication of anything.