The teenage girl, Allison, sprinted down the stairs after hearing her step-bro's bedroom door shut. She knew exactly what he was up to with their hot new step-sister, Mia. As she approached the door, she took a deep breath to gather her courage.
She turned the handle slowly and pushed the door open, ready to launch into a scolding lecture. But when she saw them, her mouth fell open in shock. Her step-bro, Bobby, had his pants around his ankles as Mia straddled him, her thin black thong disappearing into her slim ass.
"What the fuck!" Allison exclaimed, her voice a mixture of anger and disbelief. The two siblings froze, their eyes widening at the sight of their stepsister.
Mia grinned wickedly, licking her lips as she looked at the plate of chocolate chip cookies.
