Swinging of the Pendulum

Buffy has a new-maybe-sister/new-maybe-Slayer in her life, that she's trying to figure out. And she thinks that talking about that on her date with Angel (because she's finally decided to give him/them a chance) is a sure way to keep them from taking things too fast. It works... for about five minutes. Bangel. Buffy and Dawn. Angel and Dawn. Future fic. Rated T, but more M at end.