The Milk is Good

Max stared at the bottle and fought a battle in his head between his reason and his desires. He looked over to Kevin who shamelessly portrayed the bulge his about 14 inches of boner caused to his pants and shirt, and it became obvious how that latest reality change his mom did would grant him the ability to equally shamelessly enjoy walking around with his own oversized boner. None of that made the decision he was fighting about any easier. Carefully he got up and checked what had happened to his sister, as she drunk the milk as well. To his surprise she did not sport a raging boner - which would have been quite odd - instead her tits seemed to have grown massively in size. She didn't seem to care that those cantaloupes did look way out of place on her slim body though and just talked to her best friend like she wasn't sporting two gigantic orbs with very prominent and erect nipples on top. The only bad part was that none of this gave him any reason not to follow his kink deeper into the rabbit hole...

Sweat formed on his forehead when he stared at the bottle of milk in his hand, as it came closer and closer to his mouth. Eventually he took a sip, tasted the sweet strawberry flavor with a hint of growing huge in the background. Then another sip. And then he just gulped down the whole bottle at once. His gaze was empty afterwards. He knew it was stupid, and that he would regret this soon enough. But he would have regretted not using this chance even more.
"You ok?" Kevin asked when he noticed his brother shivering.
"Yeah just uh... mom called and said the milk has gone bad." Max replied.
"Why did you just drink the whole bottle then?!" Kevin returned confused.
"I... had to make sure." he lied. Not very convincing, but his thoughts were at some other place. So far the growth hasn't started, but he could swear his dick had gotten even harder just from thinking about what would now inevitably happen. "Mom told me to tell you to give me the bottle, just to be safe." he continued. Kevin stared at him like he was stupid, but eventually opened his bag and handed over his bottle of milk. It took lots of focus for Max to not gulp that thing down as well, but he managed to store it in his bag for now... and maybe a later use.
"Jill?" he then yelled through the bus.
"What?!" his sister rudely returned.
"Mom said the milk she gave us turned bad, and you need to give it to me." he told her as well, while his eyes kinda got glued at her much improved rack. A part of him wanted her to drink the milk like he did and stumble around school with tits the size of beach-balls, but his last grain of brotherly love and urge to protect her at least won that battle.
"Ewww..." Jill said and immediately handed over the bottle, which Max also stored away. Which left him with enough juice to probably turn his cock into literally tree sized. As tempting as that was, that would probably render him immobile.

They were almost at the school when Max felt the effect of his mom's breast milk start again. The feeling of his cock expanding beneath his clothes was beyond thrilling. It was literally his hottest sexual fantasy coming true, and thanks to his mom he could now enjoy it to the fullest. He felt the head of his cock crawl upwards, and his pants become tighter thanks to his expanding balls. When the bus took the last corner towards school, the tip of his cock left the top of his shirt and slowly begun to crawl further upwards at the side of his face. When the bus finally came to a stop and he had to get up, his dick was almost at the size it had been the night before: wide as a bottle of coke, and on the level of his eyes, but the growth was not yet over. It felt like edging when he walked through the bus with the upper part of his cock fully visible and still growing. The expansion came to it's final size when he entered school through the front door. His dick rubbed on his cheeks with every step, the head of it above his own, wiggling clearly visible for anyone who cared as he walked down the hallway. People looked, but apparently no one cared. Thanks to his mother's spell, this is how they knew him. The rubbing of that immense shaft on all over his body with every step though combined with the extreme erection that milk was forcing on him got him closer and closer to orgasm though, and he had no idea how long he would be able to resist that. Also the temptation of those two bottles in his bag got stronger with every passing second. He knew the effect would last for a full hour, which meant he probably just had to take another sip every 40 minutes or so to keep it going. He was also tempted to find a way to get Jill to take a sip every now and then also, those tits on her front jiggling like crazy were certainly not helping on him forming any reasonable thought. Or get her to drink the whole bottle and have her walk around with basketballs as tits. Max realized that moment how badly he had to cum...