With Yui now sagging and no longer as confident as she once was, Yui's daily masturbation has become a part of her daily routine. Yui decides to join a fitness gym to regain her former glory. However, her real goal is to meet a handsome trainer. The trainer's instructions are risky exercises that border on erotic. Things gradually escalate, and Yui and the handsome trainer begin their secret lessons, including dildo squats, stretching blowjobs, and bareback squats...