The Origin of SM
This is about reproduction, the way manhood keeps the species alive. And it is about the origine of SM.
The first part of the story is that women have the base of reproduction in nature. She produces the egg which a man have to fertilize. The number of eggs is always limited in comparison to the numerous amounts spermatozoids of the man. One egg monthly and that's ending at about the age of fourty. On the other hand a man produces millions of spermatozoïdes daily. The woman is the princess, she carries the valuable egg, she is the one in the lead. In some animals the woman eats their husband after fertilization.
This reproduction behaviour isn't something the woman invented by ratio, it's directed by an evolutionary very old part of the brain, the reptilian brain. It is the brain part that direct feeding, survival and reproduction, in short: survival of the species.
A reptile doesn't do so much in life. It's waiting till something moves in his range of view. Is it bigger, it will be wise whether running away or keeping very still. Is it smaller than catch and eat it. And if it is about the same size it would become a fight or a mate.
For this algorithme -conducting this behaviour- you don't need so much brain cells and the reptilian brain is rather small in comparison to the body volume. It's called the reptilian or reptile brain. In the evolutionary process it didn't disappear with the coming of new animals like birds, mammals and man. It is hold te be responsable for regulating the same basic processes as in reptiles, processes like food and reproduction f.e. And it's still in charge on the human species. It's only that above this old part new brain parts have been developed.
See the development of the brain from reptile to human here.
The second part of the story is SM, SadoMasochisme. A deviation in human sexual behiavour as it is called mostly. I'll explain you why it is not, that it is a normal part of the reproduction activities.
Imagine you are walking outside on the fields. It's about twilight. In the far distance you see a man walking. He is so far away that you may run away from easliy. That means that your critical fleeting distance / comfort zone ??? is big enough to escape. Will the person be within your `flight distance' than your reaction will be instinctivally attacking the person. Come close to the face of a dog don't aren't familliair with and smile with your teeths visible. Don't try this ever (I did once).
The range of the flight distance will be estimated by parameters as the distance, the surrounding (open fiels, bushes) but the size of the other as well, etc. The situation of the field is very different than when you are in the subway pressed together. There the flight distance will hardly be an inch and everything will be okay. Imagine -being within the `flight distance'- some touches the breast of a girl intendently, the reaction can only be an attack.
So far de flight distance in daily behaviour. But when you meet your love, normally you have had time enough to know eachother, you have touched lots and became acquinted eachother before mating and did the comfort zone became smaller and smaller. But then, when you want to mate, you need to break the final wall there is. Being so close to someone else that you have to cross the last barrier of the flight distance. The male duck presses with force the female under water. The human female will be under the man mostly, he is doing the job with force. So SM is nothing else as bringing down the flight distance
So one and two combined says the woman is the princess, the man is exchangeable, both are connected with ties to eachother.
* flight distance / comfort zone = the minimale distance from another being (could be an object as well) in which you may be able to run away and escape.