Dominants.. Sadists or not who recive Formal Training IE Old School/Guard spend time as a submissive in all ways but sexually. We learn to take orders and to understand just what We put a submissive through.. this does include "feeling the burn" as you speak of.. I was taught and s til try each and every new toy with the exception of insertion toys on myself again I need to know what I am dealing out.. what it feels like. the possible damages of it this has nothing to do with a masochistic streak it is simply being prudent.
This is the time during Training, a budding Sadist is given His parameters. What is acceptable. What is not. This process takes from 3 to 5 years depending on the Group at no time during Training does a Dominant play with a Sub unsupervised. After each session the Dominant is graded and critiqued by the instructor and marked in a book. This practice of formal training is not as common as it once was. The onset of the internet and the I want it now mentality of the so called doms coming in the life now make this a rarity. Formal training can still be found in Groups such as The Society of Janus or the like and in some larger clubs.
Self taught BDSM is dangerous to all involved and should be taken into account before thats before One is tied and gagged and He breaks out the chainsaw...
Be Well
J D