Just go with it

"Ok Sarah, I'm in. Mostly because I want to stay on your good side, but also because I'm curious to see what you have in mind."

"Right answer Adam! I promise you, we will have so much fun with my new powers!" Your sister says back to you.

"What if something goes wrong though? We barely know anything about all of this magic." Denise chimes in.

"What's the worst that can happen? As long as Sarah agrees to let us have our free will, and not mind control us like she did in the basement, I don't see what could go wrong. There must be some more spells in that book to fix any mistakes that happen along the way, and I'm sure Sarah has learned a lot from it, since she has severely expanded her powers by now."

"Right you are bro. This book is full of powerful magic, magic that I am anxious to tap into. Telekinesis and telepathy are great powers, but there are some others in here that are real show stoppers."

"Umm...speaking of telekinesis," Denise says, "is there any way you could let me have that power too? I found it so erotic watching you use it, and I've always loved the idea of being able to move things with my mind, well, I've loved it since I first learned about it that is."

"I seriously doubt Sarah will share her new pow-" You start to say, before Sarah waves a hand at you, shutting you up.

"I would be fine with that Denise. That way I wouldn't have to be the one doing all the heavy lifting anymore. You could help out with the fun we are all going to have."

You stare at your sister incredulously, which causes her to wave her hand at you again, allowing you to speak. "Are you serious? What's the catch here Sarah? Would you let me have that power too?"

"Nope, not you. Just Denise. I looked into her mind when she asked me, and I could see that her intentions were good. She only wants telekinesis to increase her own pleasure, and ours. And honestly, I wouldn't mind watching what she does with the power. Could be quite sexy if you ask me." Sarah winked at Denise, who just smiled and blushed. You begin to notice that there was some kind of connection budding between the two girls.

Sarah pointed at Denise, who lifted up into the air, for dramatic effect of course. Sarah's eyes glowed the familiar shade of pink as the magic book appeared in front of her, flipping to the correct page. Sarah read from the book, and you saw that an aura began to emanate around Denise. You heard her moan a little bit as she hovered there in the air. Denise was obviously enjoying the power flowing into her body. After about 30 seconds, Sarah's eyes returned to their original shade, and Denise was lowered back down to the ground. "Well, how do you feel Denise?" You ask.

"That felt amazing! Almost as good as an orgasm."

"Did it work?" You question again.

"Let's see" Denise looked at Sarah's desk towards the pen and paper that Sarah had been magically writing with earlier. The pad and paper rose up off of the desk, and the pen wrote 'I have telekinesis!'. "I am so turned on right now. All I can think about is what I can do now that I have this power!"

"Well don't be shy Denise, tell us, and we can enjoy it along with you!" Sarah says invitingly.