My close friend comes over with his latest partner... But she cheats on him and sleeps with me while he's oblivious

My best friend brought over his new girlfriend for a visit. While he was occupied, she sneaked up on me, ready to get wild. She\'s a total slut, always ready for anything. She gave me a mind-blowing blowjob, then rode me like a cowgirl. The guy didn\'t even notice, just left us to it. She took it like a champ, getting covered in cum multiple times.