A personal trainer, Mayu-onee-san, moves into the neighborhood of the reclusive young man Kanta! Worried about Kanta's lack of exercise, his mother asks Mayu-onee-san to help her. When they start intimate training at home, Mayu-onee-san's huge boobs hit Kanta's body directly! His body is loosened, but his crotch is rock hard! Unable to resist, Kanta takes advantage of Mayu-onee-san's kindness and touches her clothed boobs and ass! After the exercise, they take a shower together, and their forbidden relationship escalates! Mayu-onee-san is a lewd trainer who is completely addicted to young men's dicks...