You can't stand your step-sister-in-law and the feeling is mutual. She's always interferred, has to have the last word in every conversation, thinks she takes priority in family matters and is always right. Plus, she owes you money that you know you're never getting back and as a result, there's tension everytime you're in the same room. Unfortunately for you though, your wife's sent you on an errand to drop something by her house. Dressed in her usual low effort, baggy clothes, she welcomes you in with all the expected frosty pleasantries and passive aggression, then tells you she's too busy to chat. She tells you to make yourself at home if you want to stay, and heads upstairs. You hear the shower running. Curiosity gets the better of you and you go upstairs to have a sneaky look. You know you should leave now, but you stick around until she's in her bedroom, looking through the gap in her door to see a transformation. Hair and makeup done, sexy stockings and heels, she's sorting through a selection of underwear on her bed. You've never seen her looking like this. Distracted and hungry for a better look, you open the door too far and she catches you. A row ensues, with all the pent up grudges coming out into the open until she realises you've got an erection. She then tells you the lingerie is a treat for her partners birthday and you're going to make yourself useful by helping her choose. She tries on a few while still being rude and telling you she’s caught you eyeing her up before in the pool on holiday and at various family gatherings. She then admits that her partner is too old for her and she’s always been jealous of your wife so that’s why she’s so unpleasant. In the heat of the argument, you decide that the only way to move on is if you give into your urges and have sex to clear the tension. You hate-fuck her hard and rough while she continues to egg you on with bitchiness to motivate you. Custom name "Dave" is used.