bitchmastic Share definition Flag A tar and asbestos coating used to protect underground pipe. Otherwise known as "pipe dope", "bitch", or "dope". Most larger steel pipes in the ground that are fifty plus years old, have a bitchmastic coating. bitchmastic by sliptwat April 6, 2010 0 0 Get merch Get the bitchmastic mug. Buy Now — $32.95 See more merch