The sister, driven by curiosity and desire, corners her brother in the bathroom. His massive cock tents his pants, and she can't look away. She reaches out, tentatively tracing its length through the fabric. He lets out a low groan, encouraging her. She unzips him, her eyes widen at the sight of his monster cock. She tentatively licks the tip, tasting his pre-cum, before taking it all in, gagging as it hits the back of her throat. He grabs her hair, fucking her face, as she eagerly takes every inch.