I'm a guy, have longish hair, getting around six inches.  I part it a little off center, and have it trimmed in the very back well above my collar.  Problem is, after I wash it the bottom of the back and around my ears flips up, and the upper back gets this annoying wave, and eventually the whole back of my hair puffs up and just gets obnoxious.  The front looks fine and is straight.

It looks great in the morning (I look best when I just wake up, irony hmm?) but once I shower it just looks terrible until the next morning.  When it's a bit greasy is when it looks best.

I use that Aussie Mega shampoo and that is it.  Any ideas?  Sometimes if I comb it differently it works out better, but not always.

I have exactly this kind of hair. Unfortunately for you (but as a female, I've always thought myself fortunate with this!), you won't see a change in flippage unless you do one of two things:

1. grow it longer

2. cut it shorter

You can, of course, always use a straightening iron, but I personally wouldn't because fine hair in particular can get very damaged from heat styling.

I wish I had better news for you...