Thermasilk it's heat activated and has shine plus it's a shape gel. Works really well i had this same prob but found this stuff i thought i wouldnt work cause its cheap but omg works so awesome.
Spray your hair with hairspray 10 mins before you straighten it. It may steam or spuzz while straightening but that's just the spray, not your hair, don't worry.
3 day straightner by john frieda.... or I just wrap my hair right after and leave it for overnight then brush and go in the morning.
That makes your hair all hard and sticky and the opposite of what girls want with straight hair.