Your sister in law knows you're not getting any satisfaction off her boring prudish sister. She's seen the way you look at her, the way you lust over her curves and imagine how hot her thick pussy is. She knows all about how you've imagined she's an ani mal in bed. She's come round to help you finally get satisfied, it can be your little secret together. You're not so sure to begin with, it is cheating after all...and with her sister no less! Sister in law convinces you to atleast let her touch you somewhat so you can feel something good, she wraps her thick hot mouth around the head of your throbbing cock and sucks it hard, you can't resist her, she convinces you to let her ride your cock, and she rides it so good. She's warm and slippery as hell! As she pumps your dick harder you can feel yourself getting closer, you tell her to get off when you're about to cum like her sister does...to avoid complications...but as you're about to cum she reveals her plan to trap you, making you pump a huge load inside her fertile pussy, she explains you're going to become her secret slave from now on, and she's going to use you whenever she wants, otherwise she'll tell on you and your whole world will come crashing down. You feel the satisfaction of finally cumming hard inside a woman as the dread of what you've done begins to creep in.