A married woman personal trainer seduces me with her beautiful butt and a devilish smile, reverse NTR

Apparently my wife, who's been picky about dieting, has been hooked on a video recently. Lose weight in those 10 minutes! The female trainer shown in the video titled "They're known as Hibiki," and it appears that they are running a personal gym in Tokyo. A few days later, I ended up going to Hibiki's gym with my wife for a free trial. Hibiki was kind and polite and taught me the training, but for some reason they were strangely close. Then, in a voice that my wife couldn't hear, she asked me to take a lesson alone...