How can I change the color of a pair of shoes without making them turn stiff?

I have a pink pair of pleather/vinyl/soft plastic (I don't know how to describe the material, they are soft but mimic the look of leather) flats that I want to be black. I've changed the color of other pairs of shoes before, but when I spray paint them, they always turn stiff. How can I turn these shoes black without making them stiff? Dying them wouldn't work due to the material. Is there any paint I could use? Nail polish? Or should I just use a sharpie? I want to preserve the feel of the shoe. Thanks.