Checking the date of the last update, I realize it may have been a while since you've touched this particular story. Be that as it may, I hope you don't mind a little belated feedback.
I am absolutely loving reading This Means War. It's playful, witty, and quite honestly hilarious. I finished reading Half-Blood Prince for the first time only about a week ago, and while my head was still in the clouds, I've been seeking some fiction to prolong my enjoyment of the series. I'm glad your story was one of the first ones I stumbled upon. I'll be hard-pressed to find other stories like this to pass the time until Deathly Hallows arrives.
In any case, I hope you didn't mind some feedback from an appreciative reader. I hope to see more of your talented work as I browse.
'Lily's hangdog eyes when he had done something that went a little too far, and James' reproachful look' -- shouldn't this perhaps be 'James' hangdog eyes . . . and Lily's reproachful look'?
Very effective (and humourous) use of repetition in the story of the girls after Harry
The Talk --
This-is-the-best-fanfiction-I've-ever-read! The poetry part- did you make it up? no matter anything you do, it turns out really good! Still, as I have read all of the chapters, and am now going to review them, THe Ball?! it dissappered. a running chase. hm, THe Talk is quite funny, especialy - Padfoot gets in trouble about it . The blackmailing Mmail was pretty interesting, as it shows you put thought into this story.