James doesn't even make it to the bathroom.

"Hey, uh, thanks..." James mumbled as he got up, smoothing his track suit and pulling his tail over the hem to give it some freedom before turning around to look at his sitting step-sister. He'd expected her to look at him with the usual twinkle of mischief in her eyes, but all James found there was warmth and love. "Without you, I'd... I have no idea what I would do... probably chase cats in an alley somwhere. But having someone be there for me... go through the same changes..."

"Anytime, Balto," Lily replied, the spark of mirth returning to her face as she ran both hands over the double rows of breasts running down her torso. "But... Can I be honest with you? This is... kind of? A dream come true for me. I've always dreamed of... something like this," she finished as she indicated her own body.

"Wait, dreamed? Fantasized, like a fetish or..." James trailed off as the realization hit him. "Oh my god, my sister is a furry."

"No! No, I'm not... my... it's these three sets of nice fucking tits!" Lily turned to the side and continued much more timidly: "But... you knotting me and pulling my tail felt so good... So I'll gladly take any animal parts this will give me. And if my ears are half as cute as yours..."

Hearing Lily call his ears cute felt weird, but it was a good kind of weird, tingling deep inside his core. Embarassed, he mumbled a thanks and something about a shower before marching out of his room, his tail wagging excitedly, betraying his happiness. It was as if the appendage only partly listened to him... At least he could just stuff them down one pant leg if it got too annoying. Thinking about how he could deal with the changes, hide them from the world, James stepped towards the bathroom, only to slow his pace when he noticed something in the small decorative mirror squares his mother had hung in the hallway at around shoulder height. Stepping closer, James bent down, looked into one of them... and his eyes widened.

"LILYYYYY!" His shout echoed through the house, causing his step-sister to come running out of his room, looking worried with her tail drooping behind her.

"W-what? Is everything alright?!"

"Alright?! Why didn't you tell my that my fricking hair turned black?!" Whatever calmness James had had was quickly evaporating.

"I didn't think it was a big deal! I dye my hair all the time!"

"No big deal?! I look exactly like mom! When my hair was red, I at least..." James trailed off. "I... I need some time alone, okay? I'll take a shower and... and try to calm down."

As he continued towards the bath, James swore he felt Lily's fingers brush across his back, his step-sister reaching out but pulling back right away. He didn't care. Not really... Okay, he did, but Lily knew how he felt about the changes, about looking like his mother, and still she decided to just not mention the fact that his hair was now black. Black like his mother's.

(Author's comment: This chapter made me realize that I had some continuity issues with other chapters, so I slightly reworked them. Good thing too, it gave me a hook to unravel the secret the siblings try to keep.)