19yo Small Tits Stepdaughter Caught Masturbating

You walk into your bedroom and guess what! Your small tits stepdaughter is masturbating on your bed! Why?? She confesses she likes you so much that she was thinking about you doing it. Now what..should she continue and you watch her. No harm no foul there as long as your wife doesnt know about this. How far will this go? One thing for sure. She gets a mouthful of cum and she likes the taste of it even she spits it