Evan, caught off guard by his step-sis Nina's sudden boldness, feels his cock stir as she innocently traces patterns on his boxers. Her shy glances and soft giggles fuel his desire, and soon, his cock is a pulsing, tenting monster. Nina's eyes widen as she realizes the effect she's having, and she tentatively reaches out, touching the hot, hard length through the cotton. Evan gasps, and with a final, gentle stroke, his boxers become a cum-soaked mess, his release coating the fabric and spilling over.