The phrase "hot wax" refers to melted or heated wax that is typically used for various purposes like making candles, sealing envelopes, or removing unwanted hair. Full definition
«In working with hot wax, I found the fluid medium conducive to creating textures that became more obviously cloud and water patterns,» she explains. (torpedofactoryartists.com)
And the idea of hot wax and naked skin just seems a big no - no. (30datesblog.com)