You walk in on your step-daughter masturbating and watching porn. You watch for a minute, until she catches you. She asks how long you've been watching, noticing your hard on. You get close to her, surprising her by sliding your hand in her sweatpants. She moans for you, as you start fingering her. Hearing her wet pussy on your fingers, she moans step-Daddy over and over, kissing you repeatedly. You keep fingering her until you bring her to orgasm. Shy and overwhelmed, she thanks you for pleasuring her. She's definitely masturbating to this later, if you aren't helping her already.