This Means War - This Means, #1

LunaHe gets on my damn nerves, and I have the skill that makes me great at messing with him. We have been going back and forth for years, trying to out do the other. But something changes between us and it scares me. I shouldn't be feeling like this, and now I can't get away from him.  RydenShe is the thorn in my side, but she has always made me feel something that I couldn't understand. She has to move in with us and for some reason I couldn't be happier.
She should be off limits to me, she is my best friend's twin sister. This doesn't stop me from wanting her. How can I get her to give in to me?