using a flat iron on ALREADY straight hair - HELP!

Ok. Here's my situation.

I've got the type of hair that is naturally silky and glossy in texture, and because my genes are nice to me, it's also thick rather than fine, which is often the case for people with my hair texture. So anyway, my hair is cut to about 2 inches below my shoulders with long layers falling from neck-length and below. Well I've figured out the hard way that the natural shape of the skull makes my hair do the weird thing of the layers flipping in and the underlayers (the longest length) kind of curl inwards. Lucky for me, I have a friend with naturally course hair so the other night we decided to try using her straightening iron on my hair. Well it looked FANTASTIC. I did the method of lightly blow-drying my wet hair then straightening all of it out using a low setting on her flat iron. The end result was what i had wanted when i first got my hair cut, the layers being defined while still being casual and light.

So now I've got the issue of which products to use before using the iron. I never use hair products, even remotely strong shampoos and conditioners. I'm getting the same flat iron as her (its a professional one made by Hot Tools) but before I try doing it myself, I should probably get some sort of product.

Someone with experience in straightening already straight hair, PLEASE TELL ME WHAT TO USE!!!


-nicole