Yuki pulled my hand, looking dissatisfied, but also a little playful. Of course, there was nothing I could do at that timing, so I was carried along to the changing room on the first floor.
"Mom said it was okay, and it's been a while since we've been together, so I'm looking forward to it, you know?"
As she said this, Yuki put her hands on the T-shirt she was wearing.
"Yu-Yuki! S-So suddenly...!"
I said in a panic, but it was too late. Yuki had already taken off her T-shirt, and the amount of her beautiful skin visible had increased all at once.
"It's a bath, so I have to take it off, right...?"
Yuki was blushing a little as she spoke. I wanted her to refrain from doing so if she was embarrassed, but I couldn't help but want to look.
"I'm glad you're looking, but... I might be embarrassed if you look at me like that..."
Yuki lowered her face a little when she noticed my gaze. However, I couldn't take my eyes off her upper body, which was only covered by a simple white bra. Yuki's body was still in the process of growing, but it was starting to take on a feminine roundness.
Her breasts were slightly bulging, and her stomach looked soft, even though there was no excess fat, and I felt a healthy eroticism from her. More than anything, the sight of my active little sister in such a completely naked state aroused me.
"...Come on, Shun-nii, you have to get your clothes off too...right? Come on!"
Perhaps Yuki was feeling embarrassed, and she urged me on as well. Her breasts, wrapped in a bra, were shaking slightly as she blushed.
I had often wondered why she had suggested something like this if she was so embarrassed. I still didn't understand, but I gave up and decided to take off my own clothes. At this point, there was no other option but for us to take a bath together as brother and sister.
Yuki had washed my back before, so I was prepared for it. Still, the sight of Yuuki slowly undressing was stimulating no matter how hard I tried.
When I was down to just my boxer shorts, Yuuki started changing into more comfortable wear. They were the same white as her top, with a slight frill around the waist, and were definitely girl's wear.
She put her hands on the back of her bra and started to unhook it. Her movements seemed slower than time to me.
The bra was removed from its shoulder straps, and the cups lost their support, and it was completely removed from Yuki's chest. Yuki's younger sister's twin hills were exposed right before my eyes.
"Shun-nii, you really look at me so much... it might be kind of fun."
Yuki said something like that, and she didn't hide her breasts, and they were right in front of me. This situation would never have happened in the original world.
It may be vulgar to compare them, but they weren't as big as Sasai-san's. However, Yuki's small breasts were both cute and erotic. Her areola was small and bright pink, and the nipples that sat atop them were also a beautiful pink color.
"..."
Yuki was watching my expression and the state of my lower abdomen. I was already fully erect through my underwear, but she didn't blame me.
Yuki then said, "Okay," with a look of determination, and reached for her shorts. The thought that it would be better to stop her had already disappeared from my mind.
She slid her shorts down to her feet, and eventually pulled them off with her fingertips. Then Yuki faced me completely naked.