Unsurprisingly, yes.

While Adam was still enjoying the cum nearly clogging his throat, Katie turned to the spent dickgirl next to her.

"Listen, the thing between you and your sister kinda weirds me out, but... I'd like to repeat this. Somewhere more private. I want this prime slab of meat of yours inside my other lips," she said, zipping up her top and handing Sarah a slip of paper with her number on it.

"Wow, that's kinda archaic," Sarah grins, putting away Katie's number.

"Hey, we're not allowed our phones on the sales floor, and I can't let any cuties slip by me, can I?" the beautiful clerk answered and strode out, taking care not to step on Adam.

Still kind of dazed (or high on Growth-X cum), Sarah and Adam gathered the clothing they wanted to buy, paid and made for home. Sarah had to drag Adam most of the way to the car due to him still being out of it, so the ride back home was pretty uneventful. As they neared the house, Adam started to come to, once again stealing glances towards Sarah's crotch. His sister decided to tease him a little, pretending to readjust her package a bit. Adam moaned through lightly parted lips and started rubbing his thighs together. He had a feeling he'd need to get stuffed by Sarah's sausage sometime soon, despite having been fucked in literally every hole at least once today.

Sarah, however, had other plans for the evening. She told her cumslut brother to prepare dinner and told him she'd take care of the mess they had made in the morning. While she did clean up the bed as best as she could, the mattress was pretty much ruined. And cleaning up was not her main goal - the bottle with the remaining Growth X pills was still sitting on Adam's desk. Not for long, though, as Sarah swiped it and hid it in her room. She had decided to experiment with the pills a little; if their effects were as varied as turning one person into a more or less fully functional girl and give an actual fully functional girl a penis most pornstars would envy, who knew what they could do?

As she was thinking about the possibilities, she went down and was only half-surprised to see that her slutboy had not only prepared a modest dinner, but also changed attire: He had taken their mother's apron and put it on on top of nothing. Obviously, he hoped to seduce her with his voluptuous breasts only covered by a thing piece of fabric. And yes, the look definitely aroused Sarah to no end, but there was a certain hierarchy to be maintained.

"Very nice dinner, slutboy," she praised him, motioning for him to sit down and took the chair across from him, pretending to be wholly unbothered despite her cock threatening to rip out of her pants and bump against the table from below. Adam's face fell and he sat down, meekly eating his cheese sandwich. The crumbs fell on his oversized tit-shelf, collecting in the apron-covered valley of his boobs. A cheeky smile tugged at her mouth. After she had finished her sandwich and had enough of teasing her brother, she extended her leg below the table and slid it up her brother's leg. Her naked foot glided along his smooth leg and Adam's head shot up in surprise. Sarah wondered. Had her brother always had such smooth, hairless legs? Did he shave?

Reaching the place where Adam's legs joined (and thanking their parents for buying the rather narrow table), she started rubbing her foot on Adam's drooling snatch trough the fabric of the apron. His breath came in shuddering gasps, his eyes glazed over and he leaned forward, pressing his tits into the tabletop. Sarah grinned and got up.

"C'mon, slutboy, sit on the counter. I'll give you what you want."

Adam did as he was told and lifted the apron, revealing his reddened honeypot, still connected to the fabric with thin strings of feminine juices. Sarah freed her giant trouser snake and lined it up with her prize.

"This is what you want, right? I want you to tell me. Beg for it, slutboy."

"Oh yes, please, push it in, Sarah. Split your slutboy brother in two. Pleeeaaseee!"

How helplessly sexcrazed he had become. It was so easy to get him riled up - just like before he had grown a pussy, when she had teased him to get a rise out of him. It almost made Sarah nostalgic. Her brother was still babbling about how much he wanted it while she reminisced, he had even started bucking his hips slowly so he could get the feeling of her glans lightly parting his lower lips, so she decided to go ahead and spear him through.

A howling moan was her answer. It seemed he had been looking forward to this so much that he had been not only preparing dinner but also himself... That was more initiative than he had shown since their rather drastic shift in dynamic. She rather liked it.

As the loud moan ended and transformed into labored breaths and half-moans, she startet humping his cunt, little squelching noises mixing with their moans. Adam used both hands to stabilize himself on the counter and just focused on the feeling of being split open by his sisters, eyes shut and legs quivering. Sarah decided to kick things up a notch - taking one of her hands from his lower back, she slid the apron off one of Adam's tits and into his cleavage, leaned down and sucked his puckered nipple into her mouth, eliciting another loud moan. Despite all their fucking, Adam's nipples had been woefully neglected so far by Sarah.

The dickgirl now regretted not having done this before as she was surprised by a squirt of fluid hitting her throat. Her brother gave milk! Sucking greedily, she did her best to keep up her thrusts while gulping down the sweet substance. Adam was overwhelmed by pure bliss. Instincts he didn't know he had told him that this was right, that he was nurturing another being and that he was made for this. He grasped his sister's had and pressed her deeper into his expansive boob, his moans now turning into a mixture of cooing and soft encouragements.

Sarah kept on driving her pole into him and had soon emptied the first breast of its bounty. Switching teats after freeing it by shifting all the fabric between Adam's heaving bosom, she started sucking that one dry as well. Adam threw his head back, letting the world hear his bliss, as Sarah started lightly biting his nipple and letting her tongue play over the buzzing pleasure node.

After a particularly strong squirt of milk, she popped the nipple out and stood straight, looking right into Adam's eyes. Leaning forward, she pressed her lips against his until they parted and then opened her own. Adam's eyes shot open in surprise as a mouthful of his own breastmilk slowed into him, followed by his sisters tongue. He swallowed his milk and greeted the invader with his own tongue, relishing the slimy feeling. Moaning into each others mouth, the continued their tongue wrestling until, soon, Sarah's motions became erratic and she exploded her thick juice into her brother. His eyes rolled back and his toes curled. This was the feeling he had been waiting for, the white jism coating his inner walls! It had been so long since the last time, or at least it felt that way.

As Sarah pulled out of him, she told Adam:

"Get the kitchen cleaned up, slutboy. I'll be in my room, but you'll leave me alone until I call you in. Got it?"

For Adam, all was well with the world. He nodded dazedly and scooped up a bit of sperm leaking out of him onto the counter and sucked it off his fingers, looking at the retreating back of his sister. Oh, how he loved her. And her dick of course.

Sarah returned to her room and dug out the bottle of Growth-X. It was time to experiment!