大好きなお兄ちゃんの堕とし方 ～ツンツン妹は、兄にデレデレでした～

My little sister, Seira…
Sometimes, I think she’s charming and cute, but most of the time, she’s a mischievous little sister who loves to tease me.
Maybe it’s because of the age gap, but I’ve never been genuinely annoyed with her.
She’s got a cute face, and she’s petite—a sharp, small-framed beauty, you could say.
At least, that’s how it was… until that night.

One late night, as I was sleeping, I felt something warm and damp covering my face.
Half-asleep, I barely opened my eyes to see…
"Eh… ah… huh?! Wha—?!"
To my shock, Seira was pressing her most intimate part against my face.
"Oh, you’re awake? Hehe… you can’t escape, you know♪"
Panicking, I tried to get away, but…
Seira had already prepared for this. She’d tied me to the bed.