All three of course!

You decide that you're going to take full advantage of this situation. You pull Kelly off Zack's cock, swallow it all the way down, and then slam her pussy into his dick. Next, you shove your hard dick all the way up Kelly's ass. You can feel how tight she is and it makes you fuck her hard and fast.

You and Zack pound into her faster and faster twisting the nipples of her breast and smacking her ass until finally she explodes all Zack's dick. At the same time, you and Zack cum hard deep inside her. The three of you are sprawled out on your bed exhausted.

"Well, Kelly, as much fun as this was, I think it's time you left," you said, focusing your will on her. "Also, other than telling people we had sex, don't tell them about the things I can do."

Kelly gets up and rummages around the room for her long-forgotten clothes, gets dressed, and then kisses both you and Zack deep. "Of course. See ya later, Zack. This was fun!”

When Kelly left, Zack passed out on his bed while you stripped the sheets of yours and put them in the laundry down the hall. Then you climbed into bed with Zack and passed out. You dreamt of all the future held.