I don't really use any products to straighten (and never have) but whenever I do flat iron, I do it on dirty hair. I washed yesterday and styled with Elucence mb conditioner + castor oil + KCCC. So in a few days if I do decide to flat iron I won't prep my hair with anything. If I flat iron on fresh hair I just use my leave in (elucence) + a natural oil as a heat protectant.
Blame it on the cell phone...