Not long

You entrance Christina once more.

"Christina, you may speak normally now. However, you still may not leave without my permission. Whenever I say 'Activate', you will become a fully functional sexbot, here to pleasure me. Whenever I say 'Power Off', you will go back to normal and remember everything you did as a sexbot, and feel embarrassed and horny. Awake."

Christina straightened herself. "Um, I don't know what that was..." she said.

"Activate!" you call.

She stood up stiffly at attention, her mouth open in an O shape, her arms by her sides.

"I am Christina-bot, your personal sexual pleasure bot," she said in monotone. "How may I be of service?"

"Titty-fuck me," you order.

"Engaging titjob protocol," Christina said.

She got on her knees and lowered her dress. She began to jack you off with her hige tits.