I've seen this in reference to knowing when stainless steel cookware is ready to put oil on it, so that you don't get sticking and burning, i.e. small droplet of water shouldn't sizzle and evaporate but Leidenfrost. But I have to admit to still not being able to get the best results like that (more oil? less heat?) and still need to figure out how to use stainless correctly.
Tips?