Lol. I just meant; have a "deep container" of water or oil to plunge the blade into while making short passes on the grinder. This "quenches" or cools the metal down so you don't get the blue
or rainbow color from the heat, which will effect the metallurgy (physical) structure of the steel.
I like to just bring the grinder into the tub with me. Way easier to keep everything cool that way.