Mary's fingers trace patterns on her skin, her breath hitching as she thinks about her forbidden desires. She slips her hand into her panties, finding her pussy wet and throbbing. She strokes her clit, her hips bucking as she imagines her brother's cock filling her. She pushes two fingers inside, fucking herself slowly, her body aching for more. She bites her lip, trying to stay quiet, her body tensing as she nears her climax.