Hitozuma Fitmesu ~Biniku ni Kuikomu Leotard~

Kouji Saejima works at a sports gym.
He's an appealing fellow and a popular instructor with a formed body and polite, friendly coaching style.
But there is another side to him that dominates and plunders women, attends orgy parties of the rich and elite where sex is auctioned and bodies are trophies of sexual satisfaction. He is an animal trainer.
And he has just found a new female, Megumi Yuisaki.

[From DLsite English]