B25 is a scatological reference. The letter B is indicative of the color of ones load, while 25 indicates how many times one must wipe before finally being clean. It is not a literal indication of color and # of wipes. It's merely indicative of a hard to clean turd.
You can get in the bathroom when I'm done cleaning this b-25.
作者 The Real MC 2013年11月17日