I got an 18-year-old sister-in-law who's addicted to riding on my dick

My sister-in-law always comes to visit me in her room. I have an 18-year-old sister-in-law who's addicted to riding on my dick. The bitch is calculating, she expects my wife to take a shower and she's coming to visit me naked. She sits 15 minutes and leaves without even saying goodbye. I'm going crazy with that brand-new grump.