Then 

“What do you mean I have to strip naked!”  Mitch looked up at his towering sister with a mixture of disbelief and fury.  Allison’s beautiful face twitched as she struggled not to smile.  In all honesty he was taking this better than she had assumed he would.  “Darling, you kn-o-w I had that little scare when I shot up half an inch in a week, remember?”  He visibly calmed as his mind turned away from the present to the past.  “Yeah, you said that it was nothing…” He looked up at her accusingly.  Allison’s almond brown eyes shifted downward as she began nervously playing with her fingers.  The action caused his sister’s enormous chest to push together.  Swelling up out of her top and then sinking back down.  What stunned him most about the unintentional display of hotness was just how cute Allison still looked.  His sister was still cute despite towering over him by more than two feet!

“Hey,” his big brotherly instincts kicked in and he reached up.  He had intended to place his hand on her to reassure her, but found that rather than reach her shoulders that towered so far over his head he could reach them even while jumping, he instead made contact with his sister’s firm bare thigh.  The thick tan flesh was soft to the touch.  But underneath Mitch could feel the massive muscle that Allison’s leg possessed.  It was almost as wide as he was and a little taller too!  He was lost for a moment, forgetting everything until… “Uhm, Mitch?”  He shook his head and looked up.  Allison’s breasts blocked her face from his view when he was this close to her.  But she had stopped fidgeting her fingers.  “Its okay, sissy.”  He used the nickname without thinking.  But it seemed to work, she giggled causing her chest to bounce and ripple above him in her tight top.  

“Thanks, big bro.”  Allison was clearly pleased and refocused.  “Anyway, I didn’t want to worry you but, I kinda slipped into stage two. It turns out the Blake Virus didn’t like to be messed with.”  Mitch felt his blood run cold.  “No…”  He hissed.  Allison’s immense body descended to the ground quickly.  Mitch on instinct jumped backward.  His sister’s knee hit the ground causing a loud boom due to her size and weight.  Even kneeling, Allison loomed over him.  “Don’t be alarmed Mitch it’s okay.  We got in there, tweaked it, and everything is fine now.”  Mitch shook his head.  “So why do I need to suck your….uhm,” he stumbled.  “Milk, Mitch, you realize you’ve breastfed before, right?”  He stomped his foot.  “Yes, but not as an adult and not from my fucking sister.”  Allison sighed.  “Well, you’re just going to have to get over this silly awkwardness you have toward what is a very normal and very natural process.”

Mitch’s face twisted up, “this look natural too you?”  He gestured to himself and her.  Allison’s left lip twitched up.  She’d loved seeing him be more like his old self.  More funny, sarcastic, and confident.  “Welllll, maybe not normal for other people.”  Her smile faded and she got a very serious look on her face.  “But you need to accept,” she moved closer to him, her massive breasts squishing against him.  “This is how things are, brother dear.”  She fought against the voice inside her.  Even modified, the virus made certain changes to them, no not the obvious ones.  Increased libido, especially in the female body.  It created a combination of chemicals that made a woman feel really good about being big and lowered her inhibitions.  In the male body, the virus caused men to ooze hormones that triggered a mixed maternal and sexual instincts in even unaffected people, most likely as a survival mechanism.  End result.  The bigger Allison got the more her mind was conditioned to feel good about being big.  The smaller Mitch got the more attractive he became due to the potent chemicals his body oozed.  Subconsciously, this lead Allison and anyone with extended exposure to an infected boy to associate smaller is hotter!  

She knew all of this intellectually.  But, knowing and experiencing happened to be two different things. 

“We made it so my body produced a non-harmful variant that should regulate you.  Part of reversing my condition was us having to reintroduce the lactation inducing parts of the virus with heavy modifications.  I need to be milked, and frankly, unless you want to risk shrinking into stage two you need to start breast feeding from me daily!”   Mitch gulped.  Looking down he said in a soft voice.  “But….why naked?”  Allison just gave him a wink, “Simple, I want to make sure your body isn’t reacting poorly to the milk.”  She was lying her ass off.  She really just wanted to see him naked.  But Mitch didn’t need to know that….