Updated: NOVEMBER 27, 2017
A 'true master' is actually a play on words. It does not necessarily mean that a person is well skilled in BDSM and will respect their partner's limits. It is someone who subscribes to the mistaken idea that there are ultimate truths or only one way to practice BDSM. They use phrases such as, "A true master would..." or "A true master wouldn't..." instead of realizing that every journey is different.
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If someone refers to themselves as a 'true master,' you should pay close attention to their actions and their ideas. It means that they do not believe that anyone should practice BDSM except the way that they do it. This is actually a very dangerous concept and can lead inexperienced submissives and other BDSM players into situations that can get them injured.