You paint it onto fabric, if I recall, painting it onto dark fabric helps with the backlighting issue. Last I saw it, you could buy it in different colors, and each color required a different temperature to activate the color change. You can stick wire into the fabric and vary the resistance from the battery to get the different temperatures. It would be really difficult to attempt anything like video, but text is reasonable.
I don't know where you could buy it if you're interested, if anyone knows, lemme know.