BDSM is not dangerous, but there are some safety measures you need to apply. This is by no means a complete list and additions will follow later. (as always, tips are welcome because it's not my page but ours.) I've tried to divide the danger zones in a couple of categories and add some examples to it.
Categories:1. Agreements (between D and s)
2. Health (current)
1. Agreements (between Dom and sub)This is the category most people will refer to when they speak of BDSM and safety. It makes sense, because the other categories are usually taken for granted. Why it's not, I will explain in the other categories, but first this one; Agreements.
The mutual agreements are very important within BDSM (in a relation and one time affairs.) Simply said it means the following: Dom and the sub state their boundaries and by which these are determent. The 'by which these are determent' tells you whether its a hard or soft boundary. The difference is: A hard boundary is not to be crossed and a soft boundary is something you don't feel comfortable with (yet) but with the right person it can be stretched. What these boundaries are is very personal so the hard boundaries of a sub are not necessarily the same as the Dom's. In that case you make the first boundary to be reached the outer limit and thereby marking the common playground.
Draw 2 circles that overlap each other and mark the part that overlaps. That would be the potential common playground.
Another agreement should be the stop words or stop signs. Most commonly used are: "Mercy" and "Stop". Mercy means the Dom should slow down a little, but keep the game going. (stop what you are doing, but please don't stop entirely) Stop means STOP. The minute this word is spoken, the game is over and the session ends. This means something went wrong. Either the Dom went to far, or the sub has a problem. Many times people are afraid to use this word because they feel it makes them a bad Dom or sub. Not true, if you can use this stop word you are a great Dom or sub.
Dom or sub!! yes you read it well, Stop words are not only for subs! A Dominant can also use the Stop to end the game if He/She feels a sub is no longer capable to use the stop words and there for might harm itself by not stopping. Every time the STOP is used, you need to talk. Why did it happen? Did I miss some signal? Did my partner forget to give a signal? Was he/she ill? Why didn't I know this? etc. Was there a known boundary crossed or did you find a new boundary? Perhaps the exact definition of that boundary was not clear? Whatever it was, talk it over to prevent it from happening again. It's better to talk than to point a finger. That's why rule 1 in BDSM is: Learn. Gain knowledge. Talk and ask. (there's no such thing as a stupid question, there are only stupid answers)
2. Health (current)With (current) health I don't mean permanent disabilities, but changes in the normal healthiness of Dom or sub. This can be physical (Flue, a cold, bruises, soar throat etc.) or mental (grieve, stress, fatigue , relation problems etc.) Physical example: If a sub has the flue and can't breath trough it's nose, the Dom can't use a gag or anything else to block the mouth because the sub won't be able to breath normally. The sub NEEDS to tell about this disability to prevent possible harm to itself .
Mental example: If a Dom or sub has had a stressed week and there for can be irritated faster, it's best to tell this up front so the other party knows some limits or boundaries are reached a lot sooner than usual or reactions can be more powerful than normally.
3. DisabilityWith disability I especially mean the invisible ones which often are not experienced as a disability but in a BDSM session very well could be. So a wheelchair or a broken arm are pretty obvious and you know you need to work around it so I wont mention them here. I'm talking about simple (partly visible) things like: Lenses, hearing aid , glasses, false teeth, wig, toupee, etc. But also more serious (less visible) things like: Hearing problem (deaf), Nearsighted, night blindness, hernia, migraine, epilepsy, asthma, allergies, etc.
The possible problems with the first group could be when applying a gag or blindfold (pain caused by lenses or teeth). These problems are more an inconvenience than they are a health risk. This is because these disabilities are visible so can be worked around.
The second group can be more of a problem because the invisibility might be reason why it's not worked around. If the problem is not seen, nothing can be done to avoid any harm. Imagine a Dominant who can't hear with His/Her right ear. Now imagine you being a submissive softly asking for mercy in this Dominant's bad ear. Most likely your plea wont be heard and this specific play might end with a Stop! from the submissive. So ANY limitation has it's own reasons why it should be mentioned to your partner. If you have a problem with your knees you might not be able to kneel very long, If you have an eyesight problem you might see things happening at the very last second and cause panic. Migraine or a hernia .. well I don't need to explain the harm you can do there. Mental limitations can do probably the most damage, because you can't see the disability as well as the harm you cause.
4. OthersOther things that need to be considered are the use of alcohol, medication and drugs. The Rule is: Never play after consuming Alcohol or Drugs and as for medication: if you are allowed to drive a vehicle while using them, BDSM is not a problem. This Rule is for both Dominant and submissive. (player and to-be-played-with)
Another thing is: As a Dominant, do NOT use anything you haven't tried on yourself first. Test a new whip on your own leg or underarm, Test a knife on your own arm, Test a nipple clamp on the piece of skin between your thumb and index finger. (if that hurts, it will definitely hurt on a nipple!) Now testing a new butt plug on yourself is somewhat overdone, but gathering information on how to use it safely is smart.
Once again, BDSM is fun and this is not meant to scare you, but to keep it fun. All it means is that BDSM is not just about whipping someone's ass, but really something to take serious and something that takes lots of study. So get started and have fun, but keep it safe