I stood on the crowded platform, thighs slick, heart racing with forbidden excitement. The short pleated skirt barely covered my ass. No panties. No bra. My hard nipples poked against the thin white blouse, and my smooth, shaved pussy was already dripping.

This wasn’t just another item on my filthy bucket list.

It was part of the secret game I’d been playing with my stepbrother, Dan, for the past six months — ever since the night we both broke after Mom passed. What started as grief comfort had become something darker, addictive, and completely forbidden. He was 27, I was 22. He was the responsible older brother everyone loved. I...