無防備で無邪気な姪っ子に欲情してしまった

The story of a cute little girl Shiori and her jobless big brother. That's me.
Shiori was adorably naive. We played "show me your panties" and took baths
together, and I loved how she let me peer at her p*ssy when naked.

One day I watched Shiori pee and couldn't take it any more.
I unsheathed my penis and put it in her hands. She stroked me until I came.
That was just the start of things.