He makes them his sexual slaves.

The idea of having all three of them calling him Master, at least in the bedroom, was really appealing to Kimihito, but at the same time, he didn't want to alter their personalities TOO much... So what he had written was as follows, "Miia, Papi, and Centorea Shianus will become Kimihito Kurusu's devoted sex slaves. Any orders he gives them during sex, or to initiate some form of sexual interaction, they will happily and eagerly obey, and call him Master during any kind of sexual activity. Being his slaves for sex won't bother them in the slightest, in fact, they will love being under his power for such acts, and have no ability or desire to disobey him. This will not change their relationship outside of sexual matters however, nor alter their personalities beyond the bare minimum to make these changes.

"Miia will be the main mistress of the three, but Papi will defer to Centorea." Like heck he would let Papi have any authority over anyone. She was an adorable and lovable woman, but too much of a bird brain for that. He'd figure out if he could pull off some form of short form later.

He put the Note away as the girls were finishing up breakfast. "Hey, Cerea?" he then asked, deciding to test it.

"Yes Master?" she asked, looking at him curiously.

"Take off your top for me," he ordered, and she immediately brightened up.

"Of course Master!" she replied eagerly, pulling open her shirt, and discarding it, her majestic boobs on display.

"Good girl," he smiled at her. "Now shake your tits for me."

"As thou wish," she replied happily complying, waving them back and forth. "Does this make my breasts look better for thee Master?"

"Yes... But don't call them breasts when it's just us," he added, the idea of making a dignified woman like her use vulgar language for her assets turning him on. Miia and Papi of course watched, fascinated.