Have her join him

"So tell me Faith, and be completely honest," Xander said trying to keep composed while she stood naked in front of him. "Do you regret not be one of the bad guys ... err, girls i mean, anymore?"

"Well," Faith began taking no notice of her nudity or Xander's powers. "A little. I mean there was a great power rush, and I am not the holier then thou type like Buffy. I wouldn't mind having a little fun like I use to; but I do feel bad about the people I hurt and wouldn't do that again."

Xander smiled, exactly what he was looking for, "So; say I could make it so we could have the run of everything and have all the fun we want; without having to hurt anyone, would you be in."

"Of course," Faith replied excitedly, normally she would deny her darker side but Xander had commanded her to be truthful.

"Well then Faith, time to join up," Xander said, he then explained what had happened to him and what he wanted to do. He threw in a couple commands to make sure she didn't give any of the commands but over all he got Faith to join him willingly.

"Well then Boss," Faith began. "What do we do first?"

Xander thought about it. He knew he would probably have to go up against Buffy sometime and would like to know her weaknesses, he wanted her to join him as well. However; their was an incredibly sexy naked woman in front of who he could do anything with, maybe a little fun was in order first.