Give Niki the option of receiving the same pleasure as her sister

"No Niki," you said, "don't go anywhere just yet."

Niki froze in place. Her eyes still reflected the panic she was feeling, redoubled by her lack of mobility.

"I'm going to give you a choice," you told her, while at the same time using your new ability to rachet up her arousal. A shudder passed through her and you smiled. "In a moment you're going to experience an orgasm that's going to be just as strong as what your sister experienced at my hands. You saw how much she enjoyed it, didn't you? You can feel it building up right now, can't you?"

Niki shook her head in response, the only movement you allowed her, but you knew she was lying.

"I know you must feel disgusted and repulsed by what you and your sister just did. It's only natural. But don't you want to feel what she felt, just a little bit?" You smiled at her, more of an evil grin though.

Niki began to squirm as her orgasm grew closer. She couldn't understand why this was happening. She hated what she had done with her sister, hated it. So why was she so god damn horny? She felt even better than she had when her sister had been licking her. Why was this happening to her?

You smiled at her as she reached the brink. Her moans grew louder as she tried to cross that plateau, then more frantic as she failed to reach her peak.

"Oh, I forgot to mention this. You can only cum if you do one thing for me first." With a wish you released her, allowing her freedom of motion. Her hands flew to her pussy, three fingers of one hand thrusting in and out, the other frantically rubbing her clit.

"Well, will you do what I want so you can cum?" you asked again, a little more sharply. "Otherwise you'll never experience that orgasm you're working on. Well, will you do what I say?"