Private Libido

Why do you sleep with me?
Yuu, a delivery male escort, has a crush on his gentlemanly and sadistic customer - Mr. Saitou. But one night after embracing him, Saitou asks Yuu to move in with him?! Yuu is thrilled with the sudden development, but Saitou seems to have a hidden and mysterious side to him- Are his motives driven by love or is it just pure lust? Or…